In a medium saucepan, melt 80 grams of butter over low heat. Mix in 100 ml of milk, 100 ml of water, and ½ teaspoon of salt. Bring to a gentle boil.

In a separate bowl, whisk together 500 grams of flour and 1 teaspoon of baking powder until evenly blended.

Gradually add the flour mixture to the boiling liquids, stirring continuously until it forms a smooth, thick batter. Allow the dough to cool before adding the eggs.

Preheat your oven to 400°F (200°C). Divide the dough into two equal portions and spread in a greased baking pan. Bake for approximately 20 minutes.

In a mixing bowl, beat together the eggs and 150 grams of sugar until frothy. Gradually incorporate 50 grams of flour and 100 ml of milk, stirring well.

Transfer the mixture to a saucepan over medium heat, cooking until it thickens—about 5 minutes while stirring constantly.

Allow the cream filling to cool. In a separate bowl, whip 100 grams of cream until soft peaks form. Fold the cooled cream mixture into the whipped cream.

To assemble, spread a layer of cream filling on one cake layer, place the second layer on top, and cover the entire cake with remaining cream.

Refrigerate the assembled cake for at least two hours, allowing flavors to meld.

Before serving, dust with icing sugar or garnish with fresh fruit or chocolate shavings.