Pineapple Upside Down Cake - Gluten Free

This is Maggie's favourite cake - she chooses it for her birthday each year.

Gluten Free Pineapple Upside Down Cake
3 cups rice flour
1 cup sweet rice flour
1/2 teaspoon salt
2 cups sugar
1 teaspoon baking soda
1 teaspoon cream of tartar
1 cup butter (margarine or shortening) at room temperature
1 cup buttermilk or sour milk ** see tips
2 eggs, beaten
2 cans pineapple slices - drain and reserve the juice.
1 cup brown sugar
4 tablespoons butter- melted.
12 maraschino cherries - optional
Combine rice flours, salt, and sugar in large mixing bowl.
Add the room temperature butter - cutting in with a fork or pastry blender to make a crumbly mixture. Set aside.
In another bowl Stir together the baking soda, cream of tartar and buttermilk..  Add 2 eggs and 1/4 cup reserved pineapple juice.
Mix the wet ingredients into the dry ingredients with a wooden spoon.
Take  your 9x13 pan.  Pour in the melted butter spreading it over bottom of pan.  Sprinkle with the brown sugar.  Drain the pineapple.  Place the slices over brown sugar.  If using maraschino place in center of pineapple rings.  Cover with cake batter - it's a fairly stiff batter.
Bake at 350 for 60 minutes or until cake tester inserted in center comes out clean.
Have a baking tray on counter.  Remove baked cake.  Let cook 5 minutes.  Run a knife around outside edges.  Flip upside down onto baking tray.
Some like eating the cake hot.  Warm or at room temperature is also good.