Preheat oven to 400ºF degrees. Line a regular sized muffin tin with papers and set aside.
Mix dry ingredients: 1 cup all purpose flour, 1/2 cup whole wheat flour, 3/4 cup granulated sugar, 1/2 tsp kosher salt, 2 tsp baking powder together in a bowl with a whisk
In another bowl whisk 1/3 cup vegetable oil, 1/3 cup milk, 1 large egg, 1 tsp vanilla extract and add to the dry ingredients. Mix just until incorporated.
Fold in 2 ripe bananas that are mashed or broken into small pieces
Fill muffins cups 1/2 to 2/3 full and sprinkle evenly with 2 tbsp sanding sugar.
Bake for 20-25 minutes or until a toothpick inserted comes out clean.