In a small bowl, whisk the flaxseed and water. Allow this to stand for 10 minutes until it forms a gel-like consistency.
To Make The Topping:
Mix the almonds, oats, brown sugar, flour, cinnamon, and salt in a small bowl with a fork. Pour in the melted butter and mix until clumps form. Set aside.
To Make The Casserole:
Preheat the oven to 350°F. Spray a 2-quart baking dish or 8x8-inch pan with cooking spray.
Whisk plant-based milk, flax egg, brown sugar, salt, and both extracts until well combined. Stir in the oats.
Pour the mixture into the prepared pan. Sprinkle the berries followed by the topping over the oatmeal.
Bake for 50 minutes, or until set and golden brown. Serve with a sprinkle of powdered sugar and coconut yogurt, if desired.