Preheat your to 350 degrees F. Grease a 9-inch baking pan.
In a bowl, mix together flour, baking powder, baking soda, and salt.
In a separate bowl, pour in melted butter and sugars and mix until smooth and there are no lumps. Whisk in egg, sour cream, milk, and vanilla extract. Slowly mix in dry ingredients until no lumps remain. Slowly stir in sprinkles.
Pour batter in cake pan. Bake in the for about 35 minutes, or until toothpick inserted comes out clean.
For the frosting, blend butter until fluffy. Add powdered sugar 1/2 cup at a time until fully incorporated. Combine whipping cream and lemon curd. Mix well. Use food coloring to make the frosting your desired color.
Frost cooled cake. Slice and enjoy!
This recipe only makes 1 layer of cake. Double the recipe if you're like another layer.