This light and tasty dessert is made with just one egg and doesn’t need baking: I eat a slice for breakfast and stay full and energized until lunch.

That sounds like the perfect balance of indulgence and sustained energy! A dessert that uses just one egg, requires no baking, and keeps you full until lunch suggests a recipe that relies on gelatin or a thickening agent, and incorporates high protein/fiber ingredients.

This description fits perfectly with a No-Bake Mousse Cake or a quick, thick Pudding (like a Chia Seed Pudding or a Creamy Yogurt Cake) where the egg is used for richness and binding, not baking.

The most famous dessert matching this ease and energy profile is likely a version of No-Bake Lemon/Vanilla Cheesecake or a Protein-Rich Yogurt Mousse.

Here is a recipe for a High-Protein Lemon Yogurt Mousse Cake (using the egg for binding/richness, often stabilized by gelatin/agar, or simply relying on the thickness of Greek yogurt):

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🍋 No-Bake High-Protein Lemon Mousse Cake

This recipe utilizes the richness of the egg yolk and the high protein content of Greek yogurt to provide long-lasting satiety.

📋 Ingredients

Quantity	Ingredient	Purpose & Benefit
For the Base (Optional)
1/2 cup (50g)	Oatmeal Crumbs/Ground Nuts	Mixed with 1 Tbsp melted butter/coconut oil.
For the Mousse
1 large	Egg Yolk	For richness and color.
1 cup (240g)	Greek Yogurt	High protein for satiety.
1/4 cup (60ml)	Milk
2 Tbsp	Lemon Juice	For flavor.
1 Tbsp	Lemon Zest	Intensifies the lemon flavor.
1/4 cup	Sweetener	Honey, Maple Syrup, or preferred sugar substitute.
1 packet (7g)	Gelatin Powder	Essential for setting the cake firmly (or Agar-Agar).

🔪 Instructions (No Baking Required)

1. Prepare the Base (Optional)

1. Press the crushed oats/nuts mixed with the melted fat firmly into the bottom of a small springform pan (approx. 6 inches / 15 cm) or a loaf pan.
2. Chill the base while you prepare the mousse.

2. Prepare the Gelatin

1. In a small bowl, sprinkle the gelatin powder over 3 tablespoons of cold milk or water. Let it sit for 5 minutes to “bloom.”
2. Heat the bloomed gelatin mixture gently in the microwave (about 10 seconds) or over hot water until it is completely liquid and clear (do not boil). Set aside.

3. Create the Mousse (The 1-Egg Step)

1. In a large bowl, whisk together the Greek yogurt, remaining milk, egg yolk, lemon juice, lemon zest, and sweetener until completely smooth.
2. While whisking constantly, slowly drizzle the warm, dissolved gelatin into the yogurt mixture. Ensure it is mixed thoroughly.

4. Chill and Set

1. Pour the mousse mixture over the prepared chilled base (or directly into a small bowl/ramekins if skipping the base).
2. Cover the pan with plastic wrap and chill in the refrigerator for at least 4 hours, or until the mousse is completely set and firm.

5. Serve

1. Carefully remove the cake from the pan.
2. Garnish with fresh berries, extra lemon zest, or a sprinkle of chopped nuts.

Enjoy your energizing and satisfying “morning cake”!

Would you like a variation using Chia Seeds instead of gelatin for a vegan and even higher fiber option?