Preheat oven to 325 degrees
Grease 9 inch cake pan with butter
Cream together butter and sugar until light and fluffy
Add the eggs, one at a time, beating well after each egg
Add lemon zest and milk
Stir in flour and baking powder until just combined
Spoon batter into cake pan and smooth as best you can
Mix together ricotta cheese, lemon curd, and egg yolk
Spread completely over the top of cake batter
Sprinkle granola over the top of cake
Bake for 40 to 45 minutes, testing for doneness at 35 minutes. Cake is finished when top is mostly solid with cracks and knife inserted comes out mostly clean
Let cool
Sprinkle with powdered sugar over top and fresh berries if desired
Serve, store any leftovers in fridge