Preheat oven to 350°F (180°C).
Add frozen berries to an 8x8-inch (20cm) baking dish. Sprinkle with chia seeds and sweeten lightly with maple syrup if your berries are tart.
In a mixing bowl, stir together oats, nut butter, maple syrup, seeds, salt, and plant milk. The mixture should be sticky and hold together.
Use your hands or a spoon to drop chunks of the oat mixture evenly over the berries — it doesn’t need to fully cover them.
Bake for 35–40 minutes or until the topping is golden and crisp.
Let cool slightly, then serve with a dollop of yogurt.
