Making Vegan Berry Crumble Bars requires just a few simple steps to ensure success:

1. Preheat the Oven: Start by preheating your oven to 350°F (175°C). This is crucial for even baking.
2. Mix the Crust Ingredients: In a large bowl, combine rolled oats, almond flour, baking powder, and salt. Mix well.
3. Add Wet Ingredients: Pour in melted coconut oil, maple syrup, and vanilla extract. Stir until a dough forms.
4. Press Into Pan: Grease an 8×8-inch baking dish. Press two-thirds of the dough evenly into the bottom. This will form the crust.
5. Prepare the Berry Filling: In a separate bowl, combine mixed berries, cornstarch (if using), and lemon juice. Toss gently until the berries are well coated.
6. Layer the Filling: Spread the berry mixture evenly over the crust in the baking dish.
7. Crumble Topping: Take the remaining one-third of the dough and crumble it over the berry layer.
8. Bake: Place in the preheated oven and bake for 35-40 minutes or until the top is golden and the berries are bubbling.
9. Cool: Once baked, remove from the oven and allow to cool in the pan for about 10 minutes before transferring to a wire rack.
10. Slice into Bars: After cooling, slice into squares or rectangles.

These steps will guide you in creating delicious Vegan Berry Crumble Bars that you’ll want to share with everyone!