Preheat the oven to 350 degrees.
Drain the juice from the pineapple and maraschino cherries. Set the fruit aside. Return the cherry juice back into the jar for the remaining cherries.
Line the bottom of a 9 inch cake pan with parchment paper. Grease the sides of the pan.
Mix brown sugar and pinch of salt in a small bowl.
In a microwave safe dish, melt the butter. Pour the butter into the bottom of the pan. Sprinkle the brown sugar mixture over the butter.
Arrange the fruit in desired pattern. Return unused cherries to the jar.
Measure out gluten-free flour and baking powder into a small bowl and set aside.
In a separate bowl mix oil, egg yolks, sour cream, vanilla. Slowly stir in the sugar and mix until combined.
Add the flour mixture to the batter.
Using the whisk attachment, beat the egg whites until stiff peaks form.
Gently fold the cake batter into the egg whites until thoroughly mixed. Folding in a third of the batter at a time.
Pour the batter over the top of the fruit.
Bake for 40 minutes until an inserted toothpick comes out clean.
Cool on a wire rack for 10-15 minutes.
Turn out onto a cake plate and remove the parchment paper. Serve immediately.