Banana Nut Streusel Muffins -

Ingredients

• (1 1/2 cups plus 5 Tbsp.) all-purpose flour, divided
• (1/2 cup) whole wheat flour
• (2/3 cup) packed brown sugar
• (2 Tbsp. plus 2 tsp.) baking powder, divided
• (1/2 tsp.) ground cinnamon, divided
• (1/4 tsp.) salt
• (1 cup) mashed ripe banana
• (3/4 cup) 1% low-fat milk
• (3 Tbsp.) canola oil
• (1/2 tsp.) vanilla extract
• (1 large) egg
• (1/4 cup) walnuts, toasted and chopped
• (6 Tbsp.) regular oats
• 2 Tbsp.) butter, softened