Banana Bread Baked Oatmeal

Name: Banana Bread Baked Oatmeal
Prep time: 5 min
Cook time: 30 min
Total time: 35 min
Cuisine: American
Ingredients: 2 ripe bananas, plus 1 more for topping (optional); 2 1/2 cups (590 ml) non-dairy milk of choice; 1/4 cup (60 ml) grade A maple syrup; 1 teaspoon vanilla extract (optional); 2 1/2 cups (225 g) rolled oats; 2 tablespoons ground flax seed; 1/2 teaspoon ground cinnamon; 1 teaspoon baking powder; 1/4 teaspoon sea salt; 1/2 cup (50 g) roughly chopped walnuts (optional)