In a saucepan melt 1 cup butter and add in the brown sugar and blend well to incorporate all the melted butter.
Divide the mixture between two 9' round cake pans, arrange fresh pineapple slices in the pan, you should be able to place 4 slices in the pan, then use sections to fill in the rest of the pan. I used blueberries in the center of the pineapple, you could stay traditional and use maraschino cherries, or even use cranberries.(for a twist sprinkle the topping with chopped pecans)
In a stand mixer or a large bowl, cream the sugar with the rest of the butter until light and fluffy. Beat in the eggs one at a time and then the vanilla. Combine the flour, baking powder, baking soda, salt and cinnamon in another bowl and blend together well.
Mix the Greek yogurt and milk together and alternately add in the flour then the yogurt, 1/3 at a time. mixing well after each addition. Divide between the two pans
Bake at 350 degrees for 40-50 minutes or until a toothpick inserted near the center comes out clean. Immediately invert onto a serving platter, then allow to cool briefly.
Place a cookie sheet under the cakes, the topping may bubble out over the pan causing a mess in your oven.