A coffee cake-inspired baked oatmeal with notes of cinnamon and nutmeg and topped with an oat pecan crumb streusel.
Preheat oven to 350 degrees. Grease an 8x8 baking dish.
To a large mixing bowl, mash banana until smooth (a few lumps remaining is ok). Whisk in non-dairy milk, maple syrup, and vanilla. Add oats, baking powder, cinnamon, nutmeg, and salt. Use a wooden spoon or spatula to combine until incorporated. Pour mixture into the prepared baking dish and spread to evenly distribute.
To prepare the streusel, add pecans and oats to a high-speed blender or food processor. Blitz until a coarse meal is achieved. Add to a bowl along with the rest of the streusel ingredients. Stir until combined. Mixture should resemble wet sand. Sprinkle streusel over the oatmeal. I didn't end up using all the streusel mixture, so feel free to add as much as you'd like.
Bake for 28-30 minutes until top is golden brown and oatmeal is firm and no longer jiggles. Let cool for 5 minutes before cutting into nine even portions.