Add the chopped strawberries and rhubarb to a large mixing bowl. In a small bowl, whisk together the lemon juice, cornstarch and maple syrup until combined and then add to the strawberry mixture, tossing everything together.
In a food processor, add all the crisp topping ingredients and pulse until crumbly.
Pour the fruit mixture into an 8×8-inch baking dish, then add the crisp topping.
Bake for 40-50 minutes, then remove from the oven and let cool for 10 minutes before serving.