Preheat the oven to 400F. Line a muffin pan with muffin papers.
In a large mixing bowl, combine 2 cups flour, oats, salt, and baking powder. Whisk to combine.
In another mixing bowl, combine the oil and ¾ cup brown sugar. Beat in the eggs, then add the yogurt, bananas, and maple flavoring.
Add dry mixture to the wet ingredients and fold with a rubber spatula, just until combined. Scoop batter into prepared muffin pan, dividing evenly.
In a small mixing bowl, combine the remaining ¼ cup each flour and brown sugar. With a pastry blender, two knives held together, or a fork, cut in the butter until coarse crumbs are formed. Stir in oats. Sprinkle crumb mixture over tops of muffin batter, dividing evenly.
Bake 20 - 25 minutes until golden brown and tester comes out clean. Cool on a rack before serving.
Notes
Nutritional values are based on 1 muffin.Baked muffins are go for up to 3 days, in an airtight container.To freeze: place cooled muffins in an airtight container or ziptop freezer bag and store in the freezer for 4 to 6 weeks. Thaw on the counter prior to serving. Muffins can be warmed in a 350 degree oven for 5 minutes.