High-Protein Magic Custard Cake

~18–20 g protein per slice (9 slices)
A light, creamy, three-layer custard cake that delivers serious protein without protein powder. Soft sponge on top, silky custard in the center, and a delicate pudding base—all from one batter.

Recipe Card

Servings & Timing

Yield: 9 slices
Prep Time: 20 minutes
Bake Time: 55–65 minutes
Chill Time: 3–4 hours minimum
Total Time: ~5 hours (mostly hands-off)

Dietary Notes

High-protein
Vegetarian
Gluten-containing
Contains dairy and eggs

Ingredients

Pan: 9×9 inch (23×23 cm) glass baking dish

Wet Ingredients

4 large eggs, separated
2 extra egg whites
¾ cup (150 g) granulated sugar
½ cup (115 g) unsalted butter, melted and cooled
1¼ cups (300 g) very thick Greek yogurt (2–5%)
1¾ cups (420 ml) ultrafiltered milk or 2 cups full-cream milk
1 tablespoon vanilla extract

Dry Ingredients

½ cup (65 g) all-purpose flour
1 tablespoon cornstarch
¼ teaspoon salt

Instructions

Preheat the Oven
Preheat to 325°F (165°C). Grease a glass baking dish and set aside.
Prepare the Yolks
In a large bowl, whisk egg yolks and sugar until pale and slightly thickened.
Whisk in melted butter.
Add Greek yogurt and whisk until completely smooth.
Slowly whisk in milk and vanilla.
Incorporate Dry Ingredients
Sift flour, cornstarch, and salt together.
Gently whisk into the batter until just combined. The batter should be thin.
Whip and Fold Egg Whites
Beat all 6 egg whites to soft peaks.
Fold into the batter in three additions, using a gentle hand. Leave visible streaks; do not overmix.
Bake
Pour batter into prepared dish.
Bake for 55–65 minutes, until the top is lightly golden and the center still has a slight wobble.
Tent loosely with foil if the top browns too quickly.
Cool and Chill
Let the cake cool completely at room temperature.
Refrigerate for at least 3–4 hours to fully set the custard layer before slicing.

Quick Notes

Batter should remain thin; this is essential for proper layer formation.
Chilling is not optional—the custard layer firms only after cooling.
If the recipe inherently meets your needs for a high-protein dessert, no additional modification is required.

Brief Introduction

This high-protein magic custard cake is proof that dessert can be both indulgent and functional. Using eggs, Greek yogurt, and milk as the protein backbone, this recipe creates three distinct layers from a single batter. It’s a show-stopping bake that feels decadent but fits easily into a protein-conscious lifestyle.

Step-by-Step Cooking Guide

Mixing the Base

Whisking the yolks and sugar thoroughly ensures a smooth, custard-like texture. When adding Greek yogurt, make sure it is very thick and fully incorporated—any lumps can disrupt the final layers.

Tip: If your yogurt is cold and stiff, let it sit at room temperature for 10 minutes for easier mixing.

Folding the Egg Whites

Soft peaks are crucial. Over-beaten whites will resist folding and can collapse the custard structure. Folding in stages keeps the batter light while preserving the streaks needed for layer separation.

Tip: Stop folding as soon as the whites are mostly incorporated. Streaks are desirable.

Baking and Setting

The gentle oven temperature allows the layers to form slowly. A slight wobble in the center means the custard is set but still creamy.

Tip: Every oven is different—start checking at 55 minutes.

Ingredient Details and Substitutions

Key Ingredients Explained

Greek Yogurt: Provides structure, creaminess, and protein. Thick yogurt prevents excess moisture.
Ultrafiltered Milk: Higher protein content helps boost macros without affecting texture.
Cornstarch: Stabilizes the custard layer and prevents weeping.

Substitution Options

Milk: Use full-cream milk if ultrafiltered milk is unavailable.
Greek Yogurt: Skyr can be used for a slightly tangier flavor.
Butter: Unsalted is preferred; if using salted, reduce added salt slightly.

Equipment Alternatives

If a glass dish isn’t available, use a light-colored ceramic dish. Avoid dark metal pans, which bake too aggressively.

Recipe Variations and Serving Suggestions

Flavor Variations

Lemon: Add zest of 1 lemon to the batter.
Espresso: Add ½ teaspoon espresso powder to dry ingredients.
Vanilla Bean: Replace extract with seeds from one vanilla bean.
Cinnamon: Light dusting on top after baking.

Protein Boost Options

Choose one:

Add 2 tablespoons powdered milk, dissolved into the milk first.
Add ¼ cup extra Greek yogurt and reduce milk by ¼ cup.

Serving Ideas

Serve chilled with high-protein vanilla skyr cream.
Add fresh berries for contrast.
Slice cleanly with a warm knife for sharp layers.

Storage and Make-Ahead Information

Storage

Store covered in the refrigerator for up to 4 days.

Reheating

Best enjoyed cold. If serving warm, gently bring to room temperature rather than reheating.

Make-Ahead

Can be baked one day ahead; flavor and texture improve overnight.

Quality Notes

Layers become more defined after 24 hours.
Texture remains creamy through day three.

Nutrition Information (Approximate, per slice)

Calories: ~220–240 kcal
Protein: 18–20 g
Carbohydrates: ~22 g
Fat: ~9 g

Dietary Highlights

High-protein
Naturally vegetarian

Allergens

Contains dairy, eggs, gluten

Frequently Asked Questions

Q: Why didn’t my layers form clearly?
A: Overmixing the egg whites or using a pan that heats too aggressively can blur the layers.

Q: Can I reduce the sugar?
A: Slight reductions are possible, but too little sugar affects structure and browning.

Q: Can this be frozen?
A: Freezing is not recommended; the custard texture will degrade upon thawing.

Q: My center seems too soft—did I underbake it?
A: A slight wobble is correct. It will fully set after chilling.

Additional Notes

This recipe went through multiple test rounds to balance protein content with classic custard texture. The final version prioritizes clean layers, creamy consistency, and reliable results. If you try variations, note that even small technique changes can affect how the layers form.

If you make this cake, leave a rating and share how it turned out. Variations and questions are always welcome.