Rhubarb Coffee Cake

Name: Rhubarb Coffee Cake
Ingredients: ¼ cup coconut oil (or other oil, or butter); ½ cup agave nectar (or use sugar and add a little extra milk); 2 large eggs; ½ cup sugar; 1 teaspoon vanilla extract; ¾ cup brown rice flour; ¾ cup sorghum flour; ½ cup potato starch; 1 teaspoon xanthan gum; 2 teaspoons baking powder; 1 teaspoon baking soda; ½ teaspoon salt; ⅓ – ½ cup almond milk (or regular milk); 2 cup chopped rhubarb; ½ cup gluten free flour mix (any mix should work); ½ cup brown sugar; 3 tablespoon butter (or substitute)