1-First, start by preheating your oven to 325°F (165°C) and lining an 8×8-inch or 9×9-inch square baking pan with parchment paper for easy removal. Warm the 2 cups of whole milk until it’s just lukewarm and set it aside to ensure it blends smoothly later. This step helps the batter reach the right consistency for that magical layer separation.

2-Separate the yolks from the whites of the 4 large eggs, and whip the whites with a pinch of cream of tartar until stiff peaks form; this creates the airy top layer. Melt the 1/2 cup of butter and let it cool slightly to avoid cooking the eggs when mixed in.

3-Beat the egg yolks with the 1 1/2 cups of powdered sugar until they’re pale and frothy, which takes about a minute. Add in the 1 teaspoon of vanilla extract, 1 teaspoon of ground cinnamon, 1 teaspoon of pumpkin pie spice, and the melted butter, mixing until combined. For more flavor ideas, you might check out a similar recipe like our pumpkin cheesecake, which uses spices in a fun way.

4-Stir in the 1 cup of all-purpose flour until smooth, then whisk in the 1 cup of pumpkin puree followed by about 1/4 cup of the warmed milk. Slowly incorporate the rest of the milk on low speed; the batter should end up thin and runny to form the custard layer properly. Gently fold in the whipped egg whites with a spatula, leaving a few small lumps to keep the air pockets intact for a fluffy result.

5-Pour the batter into your prepared pan and bake for 60 to 65 minutes, or until the top turns golden and the center jiggles slightly. Once done, let the cake cool completely at room temperature before refrigerating it for a few hours to set the custard layer fully. Slice into squares and serve it chilled or at room temperature for the best texture.