- For the Base:
- 1/4 cup sugar
- 1/4 cup butter
- 1/4 teaspoon salt
- 1 egg
- 1 packet (1/4 ounce) active dry yeast
- 1/2 cup milk
- 2 1/4 cups flour
- 2 teaspoons vanilla extract
For the Topping:
- 1 cup unsalted butter
- 2/3 cup flour
- 2 cups superfine sugar
- 2 eggs
- 4 tablespoons milk
- 1 teaspoon vanilla extract
To prepare the batter:
- In the bowl of a stand mixer fitted with a paddle attachment, combine sugar, butter and salt on low speed. Add the egg, and beat on medium speed until fully combined, about 1 minute.
- In a small bowl, pour in the warm milk. Spread the yeast and stir softly until dissolved.
- Replace the stand mixer’s paddle attachment with a dough hook. To the egg mixture, add the flour, yeast mixture and vanilla. Beat for 3 minutes.
- Onto a lightly floured surface, turn the dough and knead for 1-2 minutes.
- Place the dough into a lightly greased bowl. Cover the dough with a towel and transfer to a warm dry place. Allow the dough to double in size, about 1 hour.
- Grease a 9×13-inch pan with parchment paper.
- Once the dough has doubled, punch it down. Remove the dough, and use a flexible rubber spatula to press it into the pan. Create small edges in the crust to hold the filling.
To prepare the filling:
- In a stand mixer fitted with a paddle attachment, cream the butter on medium speed until fluffy, about 2 minutes.
- Add eggs one at a time allowing the first to combine before adding the second. Add the vanilla. Add the milk gradually until combined.
To prepare the cake:
- Preheat oven to 375 degrees F with a rack in the middle position.
- Pour the topping over the dough. Use an offset spatula to evenly cover the dough. Let the dough stand for 20 minutes.
- Bake the cake until browned on the edges yet gooey in the center, about 30 minutes.
- Transfer pan to a wire rack to cool completely before serving.