In a medium saucepan, bring 1 cup of water and 1/2 cup of butter to a rolling boil over medium heat.

Once boiling, remove the pan from heat and stir in 1 cup of all-purpose flour until a dough forms.

Cook the mixture on low heat for about 1-2 minutes, stirring continuously until it forms a ball.

Let it cool briefly before adding 4 eggs, one at a time, mixing until the dough is smooth and shiny.

Preheat your oven to 400°F (200°C). Line two baking sheets with parchment paper and spread half of the choux pastry onto each sheet, forming two rectangles.

Bake in the preheated oven for 30-35 minutes or until golden brown and firm to the touch.

Once baked, remove them from the oven and let them cool completely on wire racks.

In a saucepan, heat 2 cups of milk with 3/4 cup of sugar until it’s warm but not boiling.

In a separate bowl, mix 1/4 cup of cornstarch with a splash of cold milk, creating a smooth paste.

Gradually whisk this paste into the warm milk mixture, stirring continuously until it thickens, about 5-7 minutes.

Remove from heat and stir in 2 tablespoons of butter and 1 teaspoon of vanilla extract.

Once the choux pastry layers have cooled, slice each layer in half horizontally to create four layers.

Place one half of the first layer on a serving platter and spread a layer of custard on top.

Repeat this process with the remaining layers, finishing with the second half of the last layer on top.

Chill the assembled cake in the refrigerator for at least 1 hour.

Dust the top with powdered sugar before serving and slice into portions.