Preheat oven to 350°F and line the muffin pan with liners.
Peel the apples, remove the core, and dice them. You can also shred the apples, but I love their texture after dicing them. Set aside in a medium bowl.
To prepare streusel topping, mix almond meal or flour, coconut sugar, and cinnamon in a bowl and set aside.
In a large bowl, add brown rice flour, rolled oats, almond meal, coconut sugar, flaxseed meal, baking powder, and sea salt.
In another bowl, mix the almond milk, banana, and vanilla.
Stir into the dry mixture and combine well; I used a wire whisk.
Fold in apple pieces gently.
Spoon batter into muffin liners evenly. Combine topping in a small bowl and sprinkle on top of muffin batters.
Bake for 30 minutes or until a fork inserted comes out clean. Transfer to a cooling rack and allow to cool for 5 minutes.