Low Carb Protein Cake

This low-carb protein cake is fluffy and so quick and easy to make, just mix the ingredients in one bowl with a mixer or just by hand!

It’s a simple, classic yellow cake with vanilla flavor perfect to eat plain or as a birthday cake that you can add toppings or make layers!

Low-carb protein cake slice with whipped cream and berries.

I love that’s keto, low-carb, sugar-free, gluten-free, grain-free and nut-free. It’s made without almond flour or any weird ingredients (just protein powder and coconut flour).

Ingredients needed

Gathered ingredients for low-carb protein yellow cake.

Dry

  • Whey and casein baking blend, 3/4 cup (70g) – Or just whey, see my tips on protein choices for this cake
  • Coconut flour, 1/3 cup (40 g)
  • Powdered sweetener, 1/3 cup (75 g) – It improves the texture, you can powder granular sweetener in a blender yourself if needed.
  • Baking powder, 2 teaspoons
  • Pinch of salt

Wet

  • Large eggs, 3
  • Melted butter, 1/4 cup (57 g)
  • Milk of choice (any low-carb or regular), 1/2 cup (120 ml)
  • Vanilla extract, 1 teaspoon

The eggs are American large, if you’re in Europe use medium eggs which are the most approximate in weight.

Recipe directions with photos

Before you begin preparing the protein cake:

  • Start heating your oven to 320 °F (160 °C) and
  • Line an 8-inch round pan with parchment paper and grease it with butter or oil spray. Now, here are the recipe steps:
Mixing dry ingredients.

Step 1. Mix all dry ingredients in a large bowl, using a spatula or whisk to fluff up the protein, coconut flour and sweetener and break down any lumps. Create a well in the middle of the mix to add the liquids. (I’ll explain below why if you’re not familiar with this method).

Adding liquid ingredients.

Step 2. Add the 3 eggs, melted butter, milk and vanilla in the center of the bowl. Start mixing just in the middle and as the eggs are mixed with the milk and butter start incorporating the dry mix around it, moving the mixer or whisk in larger circles.

Mixing batter.

Step 3. If you are using a hand mixer, stop and scrape the sides with a spatula at least a couple of times to ensure every little bit of the batter is well mixed.

Batter in pan.

Step 4. Transfer into the pan lined with parchment paper and greased and bake in the preheated oven at 320 °F (160 °C) for about 30 minutes until the top is golden and the cake springs back when poked with a finger in the middle.

And here’s the protein cake after baking, all golden!

Low-carb protein cake fresh out of the oven.
Looks beautiful doesn’t it? Excuse me, I have to go and bake another one!

I suggest the well method of mixing the cake because it works well. I’m lazy and don’t want to mix the liquid ingredients separately. They do end up mixing separately, sort of, inside the well, before incorporating the dry ingredients on the sides.

It will make sense when you do it, I promise.

Alternatively you could whisk the eggs, melted butter, milk and vanilla in a separate bowl and dump onto the wet ingredients. But then there would be another dirty bowl! It’s your call.

Low-carb cake with red, white and blue topping of cream and berries.

Topping ideas

This recipe makes a classic yellow cake, with a delicate vanilla flavor and not too sweet. Which makes it perfect to transform into a birthday cake or a layer cake, it tastes great with any topping flavor!

Here are a few ideas:

  • This cream cheese buttercream I used in my favorite carrot cake is thick and great if you want to make a layered cake.
  • Use chocolate frosting, it’s a delicious and classic frosting flavor for vanilla cake!
  • If you can’t get enough protein, make a protein topping! The peanut butter and whey protein frosting I used in these chocolate cupcakes would be amazing in this cake too.
  • Or simply top it with fresh whipped cream and sliced strawberries and blueberries for a red, white and blue themed cake like I did it here:
Low-carb vanilla cake topped with whipped cream and fruit cut in plate.

Honestly, it doesn’t NEED anything. This protein cake is amazing just plain! I love having it for breakfast with coffee. Hmmm…

Hot tips for the best protein cake

Use a protein blend

Excuse me for the ugliness of the comparison photos as I originally took them for myself, to keep track of the cakes baked for recipe development purposes. But I though you might be interested in seeing the differences the ingredients made so I decided to share:

Slices of cake baked with protein blend and with just whey protein side by side.
Slice of cake baked with protein blend on the left and with pure whey protein on the right. The protein blend of whey and casein had a significant better rise and it’s slightly fluffier. Taste wise, they’re about the same.

The protein baking blend ratio of 60% whey to 40% casein is the one I found ideal in testing this recipe.

If you can’t find the blend to buy, it’s easy to make it yourself.

Just mix 60% pure unflavored whey and 40% pure unflavored casein, by weight (use a kitchen scale).

For this recipe, that’s 42 grams of whey and 28 grams of casein, for a total of 70 grams. (The casein I use weights 80 grams per cup and the whey weights 100 grams per cup, yours might be slightly different).

You can also use pure unflavored whey protein, it just makes a slightly less fluffy cake (the slice on the right side in the photo above). Either isolate or concentrate is fine, the texture difference is minimal between these two.

Don’t use pure casein

I mentioned that this cake is better using a blend of whey protein and casein powders, and that the cake also works with just whey protein. But that’s not true for casein.

Without any other alterations to the recipe (still adding the same amount of liquids and coconut flour), this is how the cake looks like when baked with pure casein protein powder:

Casein protein powder cake.
The low-carb cake baked with pure casein protein powder rises in the oven but it sinks as it cools. It looks sad.

I know casein can make good cakes, but this recipe as written isn’t a good fit for it. Developing a cake recipe using casein is in my to-do list, so stay tuned.

If all you have is casein, I won’t stop you from trying, but be aware that this is the result you might get. It looks like a brick. My husband liked this cake the most, go figure.

Line pan with parchment paper

Prepare an 8-inch round pan with a disc of parchment on the bottom and (highly recommend) a strip of parchment around the sides.

All the cakes I baked before starting using the parchment got way too dark around the sides. They didn’t burn, just looked like they had.

Protein powder causes cakes to brown quicker. The batter is also super sticky, and the cake can be difficult to unstick from the pan without the paper lining.

Does adding xanthan gum make a difference?

Slices of low-carb cake baked with xanthan gum and without xanthan gum side by side.
Slice of cake without xanthan gum on the left and with 1/4 teaspoon of xanthan gum on the right. The cake with xanthan gum has tighter crumb with less air holes and slight better rise. No other significative differences.

I tested adding xanthan gum to see how much better the cake could get, but the difference is more visual than anything.

So I chose to keep it simple, and did not add xanthan gum to my final recipe version.

If you are making an elaborate layered cake like a keto birthday cake or if it’s going to be sold or photographed (for a wedding, for example), then you might want to add xanthan gum to make it more attractive.

Developing the recipe

I have been developing this recipe for a while. I baked a total of 9 cake variations, tweaking the ingredients slightly in each one until I got the winner recipe.

I got the idea for this recipe from seeing how successful the new keto box cake mixes are (example: Duncan Hines Yellow Cake Mix). I haven’t tried any unfortunately as I live in Europe and they’re not available around this parts. However, I read the ingredients lists on them all to help me create my own, and noticed that most of them have both almond and coconut flour, and that the first ingredient is usually erythritol, which may be too sweet for some.

I tested my recipe with a range of sweetener amounts. Most low-carb people I know are used to eating low to no sugar so the lower amount of sweetener will be more than enough. But you can use the higher amount if you have a serious sweet tooth.

Slice of protein cake with berries and whipped cream.

Another problem with the low-carb cake box mixes is the prevalence of almond flour. It sucks if you can’t have nuts, are avoiding anti-nutrients or just don’t want the excess calories from eating a ton of almonds.

So I worked to create the easiest keto cake. With simple and few ingredients, and with the best macros out there (more protein, less carbs, less calories and fat – I’m not interested in extra calories!).

A cake that I could eat as much as I wanted, whenever I wanted.

I think I got it. And now I want to share my favorite easy keto cake recipe with you!

By easy cake, I mean:

You can just throw all ingredients in a bowl and mix by hand if you have to. No creaming butter and sugar separately. No whisking egg whites in a separate bowl and then folding it in.

I get it, sometimes you want to make a spectacular cake and go all in and spend a day in the kitchen. I’d argue that often you are in for diminishing returns.

Tell me if I’m wrong: Most of the times you just want a simple cake and are more in the mood for eating than for baking. And when you’re trying to eat healthy it’s not as simple as going to the store and picking a cake up. This is where this protein cake recipe comes in.

I hope you like the recipe! If you make it, please share your review with a comment below and tag a photo of your cake @likehotketo, I’d love to see it!


Low-carb vanilla cake cut in plate.

Low-Carb Protein Cake

5 from 2 votes
A basic 8-inch yellow cake recipe made with protein powder and coconut flour. This fluffy vanilla cake is delicious plain or as a keto birthday cake with your favorite toppings.
Author: Pris Frank
Prep Time 5 minutes
Cook Time 30 minutes
Total Time 35 minutes
Course Dessert
Cuisine American
Servings 8

Ingredients
 

Instructions
 

  • Start heating the oven to 320 °F (160 °C) and prepare an 8-inch round pan with a disc of parchment on the bottom and a strip of parchment around the sides. Grease the paper lightly with butter or oil spray.
  • Mix all dry ingredients in a large bowl until combined: 3/4 cup protein blend for baking, 1/3 cup coconut flour, 1/3 to 1/2 cup powdered sweetener, 2 teaspoons baking powder and 1 pinch salt.
  • Create a well in the middle of the dry ingredients and add 3 large eggs, melted (but not hot) 1/4 cup butter, 1/2 cup low-carb milk and 1 teaspoon vanilla extract.
  • Start mixing from the middle and as the eggs are mixed start incorporating the dry mix around it , scraping the sides. If you are using a hand mixer, stop and scrape the sides with a spatula at least a couple of times to ensure every little bit of the batter is well combined.
  • Transfer into the pan lined with parchment paper and greased and bake in the preheated oven at 320 °F (160 °C) for about 30 minutes until the top is golden and the cake springs back when you poke a finger in the middle.

Notes

This protein baking blend ratio of 60% whey to 40% casein is the one I found ideal in testing this recipe. You can also use pure unflavored whey protein, it just makes a slightly less fluffy cake. Either isolate or concentrate is fine, the texture difference is minimal between these two.
The cake baked in a 8-inch round pan is about 1 3/8 inches (3.5 cm) in height.
The cake can be made in a 9-inch pan but it will be thinner. The baking time will be shorter too, start checking for doneness at around 25 minutes.

Nutrition

Serving: 1sliceCalories: 136kcalCarbohydrates: 4gProtein: 12gFat: 8gFiber: 2gSugar: 1gNet Carbohydrates: 3g
Tried this recipe?Leave a comment and let us know how it was!

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