This all purpose crumb topping is good on pies, fruit crisps, coffeecakes, muffins, you name it. I like using Sorghum and Chickpea or All Purpose Sorghum blends, but Bob's Red Mill All Purpose Gluten Free Flour Blend works well too.
Go here for Nut Free Crumb Topping.
1 cup GF flour blend
1/4 cup brown sugar
2 tbsp. white sugar
1/2 tsp. cinnamon
8 tbsp. dairy free, soy free margarine
1/2 cup finely chopped pecans or walnuts
Whisk together the flour, sugars and cinnamon. Cut in the margarine with a pastry cutter until the mixture resembles small crumbs. Stir in the nuts and toss well. Bake according to your recipe instructions.