Preheat the oven to 375′. Divide the berries between six small mason jars if using. or put on the bottom of a baking dish
Mix the oats, cinnamon, baking powder and salt in a bowl. Divide the dry mix between the jars if using, just layering on top of the blueberries, about 1/3 cup; or, pour over the berries in the baking dish.
Mix the milk, butter, maple and vanilla together. Pour a scant 1/2 cup on top of the oats if using jars, letting it seep through to the bottom. Pour evenly over the oats if using a dish. Place all the jars in a baking dish, sprinkle a few fresh berries on top, and bake on the middle rack for about 30 minutes until the liquid is absorbed, tops are just browned but the oats are still moist.
Sprinkle the tops with the toasted almonds and serve warm!