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Soft, thick, bakery-style birthday cake protein cookies with a tender center, creamy frosting, and surprisingly easy prep from start to finish.

An actual birthday cake crumble cookie can hit close to 800 calories each, and that wont help you meet your macros.

If you want the same nostalgic flavor but something that will fit into the high protein (30g protein per cookie), low carb lifestyle, this is the recipe for you.

These 30g protein birthday cake Crumbl cookies are soft, frosted, and bakery-style with lower carbs and high protein, making them the perfect guilt-free dessert for Crumbl lovers.

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The star of the show

If you want to recreate that nostalgic birthday cake flavour, you absolutely need this cake batter extract. Plain vanilla wont cut it.

Get it on Amazon

Why You Will Love This Recipe

Each cookie packs a massive 30 grams of protein

-Soft and thick like a bakery cookie, not dry or chalky

– Lower carb and sugar-free when made as written

– Tastes like real birthday cake, not a “protein dessert”

– Easy one-bowl dough with simple ingredients

– Make-ahead friendly and stores well for the week

– Way more filling than a traditional Crumbl cookie

Ingredients You Need

Vanilla whey–casein protein blend

This is critical. The casein helps create structure and softness. Whey-only protein will bake up drier and more cake-like. You can use whey alone, but expect a noticeable texture change.

Oat flour

Adds softness and structure. Do not replace entirely with protein powder. If you need lower carbs, you can reduce slightly, but removing it fully will make the cookies dense.

Zero-calorie granulated sweetener

Use a monk fruit or erythritol blend that measures cup-for-cup like sugar. Liquid sweeteners will not work the same.

Coconut flour

This absorbs moisture and balances the yogurt. Almond flour can be used instead, but the cookies will spread more and be slightly softer.

Baking powder

Gives just enough lift so the cookies don’t bake up flat.

Salt

Do not skip this. It balances the sweetness and enhances the cake batter flavor.

Fat-free Greek yogurt

Provides moisture and protein. Full-fat yogurt will work but will increase calories and change macros.

Egg

Binds everything together. Do not substitute flax egg here or the texture will suffer.

Light butter, melted

Adds richness without making the cookies greasy. Coconut oil can work, but butter gives better flavor.

Cake batter extract

This is what gives the classic birthday cake flavor. Vanilla alone will not replicate it.

Icing ingredients

Fat-free Greek yogurt forms the base. Powdered sweetener keeps it smooth. Birthday cake whey adds flavor and protein. Whipped cream cheese adds structure. Sugar-free pudding mix thickens and stabilizes the frosting. Skipping the pudding mix will result in a loose icing.

Step-by-Step Directions

Preheat your oven to 350°F (177°C) and line a baking sheet with parchment paper.

In a large bowl, whisk together the protein powder, oat flour, sweetener, coconut flour, baking powder, and salt until fully combined.

Add the Greek yogurt, egg, melted butter, and cake batter extract. Mix until a thick but scoopable dough forms.

Divide the dough into four equal portions and place them on the baking sheet.

Gently press each portion down slightly. Do not flatten completely.

Bake for 10–12 minutes until the edges are set and the tops look just firm to the touch.

Remove from the oven and let the cookies cool on the counter for 20 minutes. This step is crucial for final texture.

While cooling, mix all icing ingredients in a bowl until smooth and thick.

Once cookies are fully cooled, spread icing evenly on top.

Tips for Success

Do not overbake. My first test batch went two minutes too long and turned dry fast. Pull them when they still look slightly underdone in the center.
Use whey–casein blend protein. This cannot be stressed enough. Whey alone will change everything.
Let the cookies cool completely before icing. Warm cookies will melt the frosting.
If your dough feels sticky, let it rest for 2–3 minutes so the coconut flour can absorb moisture.
If swapping coconut flour for almond flour, expect a softer cookie that spreads more.

Frequently Asked Questions

Are these keto-friendly?

They are low carb and sugar-free, but not strict keto due to the oat flour. Net carbs are still significantly lower than traditional cookies.

Can I use whey protein only?

Yes, but the cookies will be drier and less soft. A whey–casein blend gives the best Crumbl-style texture.

How should I store these cookies?

Store in an airtight container in the fridge for up to 5 days. They also freeze well for up to 2 months.

Can I skip the frosting?

You can, but the frosting adds moisture and completes the birthday cake flavor. Without it, the cookies will feel more like protein muffins.