1-½ c all purpose gf flour
1 c sugar
1tbs baking powder-gf
1/2 c vegetable oil
¼ c. milk
2 lg. eggs beaten to blend
1/3 c. firmly packed light brown sugar
2 tsp cinnamon
3 tbs unsalted butter, cut into small pieces
Preheat oven to 300 f. Mix first 3 ingredients in a large bowl. Add oil, milk and eggs and stir until dry ingredients are just moistened. Transfer batter to an ungreased 8in square baking pan. Sprinkle with brown sugar, then cinnamon. Dot top with butter.
Bake until tester comes out clean, about 50 minutes. Cool slightly and cut into squares to serve.