Preheat and prep: Heat the oven to 350°F (175°C). Lightly grease an 8x8-inch or 9x9-inch baking dish.

Combine dry ingredients: In a large bowl, stir together rolled oats, baking powder, cinnamon, and salt until well combined.

Whisk the wet ingredients: In a separate bowl or large measuring cup, whisk milk, eggs, maple syrup (or honey), vanilla, and melted coconut oil (or butter). If using lemon zest or almond extract, whisk it in here.

Bring it together: Pour the wet mixture into the dry ingredients and stir until the oats are evenly moistened.

Add blueberries: Gently fold in the blueberries. If using frozen, add them straight from the freezer.

Pour and top: Transfer the mixture to the prepared dish. Sprinkle sliced almonds evenly over the top.

Bake: Bake for 35–45 minutes, until the center is set and the top is golden. The edges should be lightly browned and pulling away from the sides.

Cool slightly: Let it rest for at least 10 minutes before slicing. This helps it firm up.

Serve: Enjoy warm as is, or top with a splash of milk, a dollop of yogurt, an extra drizzle of maple syrup, or a few fresh berries.