Banana Cake with caramel sauce (Mennonite girls can cook)

Cake
1 C butter or margerine
1 1/2 C sugar
3 eggs
1 1/2 tsp xantham gum
1 tsp vanilla
3 mashed bananas
1 C buttermilk ( I often use buttermilk powder)
1/4 tsp salt
3 C GF flour (I use either the featherlight mix or asian rice flour)
2 tsp baking soda
2 tsp baking powder
Caramel sauce
2 tbsp butter
1/3 C brown sugar
1/3 C sour cream
Mix together the butter and sugar. Beat in the eggs, vanilla, bananas and butternilk. Stir in dry ingredients until well blended. Pour into a greased 9x13 pan or 2 9 inch round pans and bake at 350 degrees for about 45 minutes or until set in the middle.
While cake is cooling, make your caramel sauce.
Melt the butter in a small saucepan over medium heat. Add sugar, cook until melted. Stir in the sour cream and cook for 1 minute. Drizzle over your cake slice and enjoy!