Preheat oven to 350°F. Swirl 1/4 cup melted butter into the bottom of the pan, brushing to get into pattern of pan and up sides. Sprinkle with 1/2 cup brown sugar. Arrange the pineapple slices and cherries into the pattern in the bottom of the pan. Mix all wet ingredients together in a bowl. Mix dry ingredients together in a separate bowl and mix into dry ingredients until incorporated. Pour over pineapple and cherries and bake for 45-55 minutes, until toothpick inserted comes out clean. Allow cake to cool for 5 minutes in pan before inverting onto a serving plate. Cool cake well before and slicing and serving.