Two-percent Greek yogurt or low-fat milk, for serving, optional
Preheat the oven to 350 degrees Fahrenheit. Using the butter, grease a 2-quart baking dish or an 8-inch square baking pan.
In a large mixing basin, whisk together the oats, sugar, and 1/8 tsp salt. In a medium mixing dish, combine the almond milk, egg, vanilla, and almond extract. Pour the milk mixture over the oats and stir thoroughly to incorporate.
In a medium mixing bowl, combine the almonds, oats, sugar, butter, flour, cinnamon, and 1/8 tsp salt until evenly incorporated.
Fill the prepared baking dish halfway with oatmeal. Place the berries on top of the oatmeal, including any liquids. Add the toppings last. Cook for about 50 minutes, or until lightly browned and set. Allow 10–15 minutes to cool on a rack. If desired, top with a dollop of yogurt or a splash of milk and serve warm.