Gather the ingredients and preheat the oven at 375℉.
The Mixing
In a large mixing bowl, combine the 155 g all-purpose flour, 90 g rolled oats, 135 g sugar, 1 1/2 tsp. baking powder, 1 tsp. baking soda and 1/2 tsp. salt. Mix well.
In a separate mixing bowl, beat together 1 egg, 5 banana and 75 g unsalted butter until smooth. You can mash the bananas before but can also do it with the others.
Stir together the dry and wet mixes with 100 g cranberries until well combined.
The Baking
Spoon batter into lined muffin pan, filling almost to the top.
Bake on the middle rack at 375℉ for 25 minutes or until the top springs back when lightly touched.
The Serving
Enjoy them warm or at room temperature; they pair beautifully with tea or coffee, making for a delightful healthy breakfast or a satisfying dessert.