Philadelphia-Style Butter Cake

For the cake:
Preheat oven to 375 F.

Put the warm milk in a small bowl. Dissolve yeast in the warm milk, then set aside.

In the bowl of your stand mixer, cream butter, sugar and salt. Add egg and beat one minute until well blended. Add flour and mix to combine. Then add the milk-yeast mixture and vanilla to the batter. Mix for three minutes with the dough hook or by hand. If mixing by hand, turn out onto a floured board and knead for one minute. Otherwise, this can be kneaded using the dough hook with your stand mixer.

Place dough in a lightly greased bowl, cover with a towel and set in a warm place to rise for one hour or until doubled. Meanwhile, prepare topping and then set it aside.

For the topping:

In a medium sized bowl, cream butter. In another bowl, stir together flour and sugar. Gradually beat the sugar mixture into the butter. Add eggs, one at a time, beating well after each addition. Add milk, one tablespoon at a time, just until the mixture reaches a spreadable consistency. It should still be thick!

Putting it together:

Pat dough into a 9×13 pan, bringing dough halfway up sides of pan to hold the filling. Prick dough all over with a fork. Pour topping over dough, spreading evenly. Let cake stand 20 minutes before baking in the preheated oven for 30 minutes. Do not over-bake! (I cannot overstate this). Topping should be crusty, but gooey. It should jiggle slightly when shaken. Allow cake to cool before cutting.