Preheat oven to 425°F. Prepare a 12 cup muffin pan (or two if you happen to have two pans) with liners or baking spray. In a large bowl or stand mixer, add flour, oats, brown sugar, baking powder and cinnamon. Top off with mashed bananas, softened butter and egg. Begin mixing on low, slowly pouring in the half and half as it mixes. Continue mixing until all ingredients are incorporated well. Pour in chopped walnuts and give another quick mix until dispersed throughout the batter. You can also opt to stir the walnuts in by hand if you prefer.
Using a large cookie scoop, divide batter among muffin cups with one large scoop each. If using only one muffin pan, reserve extra batter to make additional muffins later.
In a small bowl, mix together 2 tablespoons sugar and 3/4 teaspoons cinnamon. Top off muffin batter with a spoonful of cinnamon sugar mix.
Bake muffins for 15-20 minutes or until a toothpick comes out clean.
Cool for several minutes in the pan, then transfer to a cooling rack to cool completely. Store in an airtight container for up to several days.
Nutritional information is provided as a courtesy and is an estimate only. Nutrition information can vary for a variety of reasons. For the most accurate data, use your preferred nutrition calculator with the actual ingredients you used to make this recipe.
Did you make this recipe?I'd love to see it! Snap a picture and tag @bakedbyrachel on Instagram!