Gluten Free Pumpkin Streusel Cake

Here is a gluten free version of the Pumpkin Streusel Cake. It is important to use the Authentic Foods White Rice Flour Superfine, if possible. Their flour minimizes the grittiness that you get with regular rice flour or sweet rice flour. Make sure you use potato starch, not flour.
1 cup superfine white rice flour
1 cup potato starch
1 tsp xanthan gum
2½ tsp baking powder
1 tsp salt
1½ tsp cinnamon
½ tsp ground ginger
¼ tsp ground cloves
tsp ground allspice
½ cup dairy free margarine (I use Fleischmann’s Unsalted Margarine sticks)
1 cup dark brown sugar, packed
1 cup granulated sugar
2 eggs
1 tbsp vanilla extract
1 (15 oz.) can pumpkin puree (I use Libby’s Pure Pumpkin)
1 cup rice milk (soy, almond or coconut will work too)
·      Preheat oven to 350°F.
·      Grease and flour a 9×13 inch pan.
·      In a bowl, whisk together flour, baking powder, salt, cinnamon, ginger, cloves, and allspice.
·      Beat margarine and sugars together until combined.
·      Add eggs, vanilla, and pumpkin.
·      Mix until smooth.
·      Add dry ingredients alternating with the milk, beginning and ending with the flour mixture.
·      Pour into the prepared pan and sprinkle the top with the crumb topping. It will seem like a lot, but some of it sinks into the top of the cake.
·      Bake 45-55 minutes or until a toothpick comes out clean.
Crumb Topping
4 tbsp cold dairy free margarine
1 cup packed dark brown sugar
¾ cup superfine white rice flour
¾ cup potato starch
½ tsp salt
½ cup chopped pecans (optional)
½ tsp cinnamon
·      Mix together the superfine white rice flour, potato starch, salt, and cinnamon.
·      Add the brown sugar and blend until thoroughly combined.
·      Cut in the cold margarine with a pastry cutter, forks, or your fingers.
·      Add the pecans.
·      Sprinkle on top of the cake.