Preheat the oven to 375°F (190°C) and grease an 8×8-inch baking dish with coconut oil.
In a large bowl, combine the oats, baking powder, ground cinnamon, and salt. Mix well.
In another bowl, whisk together the almond milk, maple syrup, beaten egg, vanilla extract, and melted coconut oil.
Pour the wet ingredients into the dry ingredients and mix until fully combined. Optionally, fold in raisins and chopped nuts.
Transfer the oatmeal mixture into the prepared baking dish.
In a small bowl, mix the coconut sugar, ground cinnamon, and melted coconut oil to make the cinnamon swirl. Drizzle over the oatmeal and swirl with a knife.
Bake for 35-40 minutes until the top is golden brown and the oatmeal is set.
Let cool for a few minutes before serving. Optionally, top with extra maple syrup or yogurt for added creaminess.