Banana bread was always a staple in my mom’s kitchen when I was growing up. Over the years, I have riffed on her recipe in dozens of ways: adding chocolate chips, nuts, or spices; swinging from quick bread to cake; icing or dusting it with confectioners’ sugar. Then, about a year ago, I decided to play with the idea of a banana upside-down cake, topped with banana slice and salted caramel, which both soaks into the cake and drips all around it when the pan is inverted. That little idea turned out to be a total keeper. Here it is.