Snickerdoodle cake

Ingredients:

Cake

• 165 g butter, room temperature + a little for greasing the pans
• 2.5 cups of flour
• 2 tsp baking powder
• 1 teaspoon ground cinnamon
• 0.5 tsp fine salt
• Protein of 6 large eggs
• 1 cup whole milk, room temperature
• 1 tbsp vanilla extract
• 1.5 cups of sugar
• A pinch of cream of tartar

Butter cream

• 3/4 cup + 1 tbsp sugar
• A pinch of fine salt
• Protein of 6 large eggs
• 450 g butter, cut into 4 cm pieces, room temperature
• 1.5 tsp ground cinnamon
• 0.5 tsp vanilla extract

Preparation:

1. Bake the cakes: Preheat oven to 175°C. Grease two 22cm cake pans and line the bottoms with baking paper.
2. In a medium bowl, whisk together the flour, baking powder, cinnamon, and salt. In another medium bowl, beat together the egg white, milk, and vanilla. In a large bowl, beat together the butter and sugar with a mixer on medium-high speed until light and fluffy. Add about a third of the flour mixture and mix thoroughly on medium-low speed. Then add a third of the egg-milk mixture and continue mixing on medium-low speed, scraping down the sides of the bowl as needed. Repeat with the remaining flour and egg mixture, finishing with the flour. Pour the batter evenly into the prepared pans and bake for 25 to 30 minutes, until the cake springs back when pressed and a toothpick inserted into the center comes out clean. Place the cakes in the pans on a wire rack and cool completely.
3. Prepare the butter cream: In a saucepan that can accommodate the bowl of a stand mixer, add a little water and bring to a boil.
4. Place 3/4 cup sugar, cream of tartar, salt, and egg whites in the bowl of a stand mixer and mix by hand. Place the bowl over simmering water and beat until the mixture is warm to the touch and the sugar is completely dissolved. Transfer the bowl to a stand mixer fitted with a whisk attachment and beat on medium-high speed until the mixture cools and stiff peaks form, 10-15 minutes.
5. Add the butter a couple of pieces at a time, mixing well after each addition. Once all the butter is incorporated, continue beating on medium-high speed. The mixture will collapse and look curdled. Continue beating until smooth and creamy. Stir in 1 teaspoon of cinnamon and vanilla.
6. In a small bowl, combine the remaining 1 tablespoon sugar and 1/2 teaspoon cinnamon.
7. Assembly: Cut each cake layer in half horizontally to make three round cakes (reserve one of the bottom layers for the top layer). Place one round on a cake stand or serving platter and spread about 1 cup of buttercream frosting all the way to the edge. Sprinkle with cinnamon sugar. Layer two more layers of cake layers, buttercream frosting, and cinnamon sugar in the same manner. Top the cake with the final cake layer (bottom side up). Cover with the remaining buttercream frosting and sprinkle with the remaining cinnamon sugar. Let the cake rest for at least 1 hour, then slice and serve.