Add melted butter to prepared pan and allow it to spread to the edges.
Sprinkle brown sugar evenly over melted butter.
Lay the pineapple slices on top of the brown sugar.
Place the cherries in the middle and between the pineapple slices and press lightly into the brown sugar.
For the Cake:
In a small mixing bowl, whisk together the gluten free flour blend, baking powder, baking soda, and salt until combined. Set aside.
In a large mixing bowl, add the butter and sugars and beat with an electric mixer until combined.
Beat in the egg, vanilla, sour cream, and pineapple juice until completely combined.
With a wooden spoon, stir the flour mixture, ½ at a time, into the wet ingredients until just combined.
Carefully spoon the cake batter over the pineapple slices/maraschino cherries. Use a knife or off-set spatula to smooth the batter around the pan.
Bake for 30-35 minutes until golden brown and a wooden pick inserted in the middle comes out clean.
Allow cake to cool on a wire rack for 20 minutes.
Run a butter knife around the edge of the pan to release the sides of the cake. Place a flat plate over the top of the cake. Holding both the plate and the cake pan together, carefully flip the cake onto the plate.
Cool the cake completely before slicing and serving.
Drain the pineapple slices and maraschino cherries and blot dry. After you’ve drained the fruit, use a paper towel to blot any excess moisture. Too much moisture from the fruit can lead to a mushy cake.
Use oven mitts or a thick kitchen towel when flipping the cake upside-down. After cooling for 20 minutes, the pan will still be very hot. If you don’t have oven mitts, place the cake pan on a thick kitchen towel before flipping, to protect your hands.
After you flip the cake, slowly lift the pan. If it feels like the cake is sticking, tap on the bottom of the pan and shake it a little to get the cake to release from the pan. Don’t worry if any of the topping sticks to the pan. You can still use a spatula to remove the stuck piece(s) and re-attach to the top of the cake.