Preheat oven to 350 degrees. Roll out your pie dough and place it into your pie plate. Trim and flute the outer edge, then chill under plastic wrap while you prepare the fillings.
In a large bowl, place butter and sugar. Beat until creamy and light. Add the egg and mix until combined. Then mix in the milk.
In a separate bowl, combine flour, baking powder, and salt.
Next, add the dry ingredients to the wet, mixing just until smooth. Avoid over mixing so your cake stays tender.
Spread half of the cake batter evenly into the unbaked pie crust.
In a small saucepan, whisk together cocoa powder, sugar, and boiling water until smooth. The mixture will be thin — that’s exactly right.
Gently spoon or pour half of the chocolate mixture over the top of the batter. Don’t stir it in; just let it sit on the surface. During baking, the chocolate layer sinks to the bottom of the pie, forming that signature fudgy base — the reason it’s called Funny Cake. (Follow the same process with the second pie.)
Place the pie on a baking sheet and bake for 35-40 minutes until the top of the cake is golden and set. A toothpick inserted near the center (not through the chocolate layer) should come out clean.
Allow the pie to cool on a wire rack. Serve slightly warm or at room temperature.