Mixing Ideas: Add ½ to ¾ cup dark chocolate chips, chopped walnuts, or chopped pecans to the batter before baking.
Variation of the Streusel topping: Combine ¼ cup rolled oats, 2 tablespoons flour, 1 teaspoon pumpkin pie spice, ¼ cup turbinado sugar, and ¼ cup salted butter, cut into pieces. Cut in the butter using a pastry cutter or fork until a crumbly streusel forms. Sprinkle on top before baking.
Frosting option: Make 1 recipe from this Maple frosting and spread it over the muffins with a fork. Or use a salted caramel glaze from this Banana Bread with Brown Butter recipe.