½ C butter
1 C GF flour blend
2 C sugar
1 T baking powder ( adjusted to sea level)
1/8 t salt
1 C milk
4 C fresh peach slices
1 T lemon juice
1 C sugar

Melt butter in a 13x9 baking dish
Combine flour, 1 C sugar, baking powder, and salt.  Add milk, stirring just until moistened.  Pour batter over butter, but don’t stir.
Bring remaining 1 C sugar, peach slices, and lemon juice to a boil over high heat, stirring constantly. Pour over batter, but don’t stir.  Sprinkle with cinnamon and sugar if desired.  Bake at 375 for 45 min or until it passes a toothpick test.  

I used flour blend #3:
¾ C white rice flour
4 C potato starch
5 T guar gum
½ C albumen (powdered egg whites)