Perfectly sour and sweet, the rhubarb and strawberry filling is a delightful contrast paired with the buttery and crumbly topping.

Preheat the oven to 375 degrees F.

For the topping:
In a medium bowl, whisk together the flour, baking powder, salt, granulated sugar, brown sugar, and lemon zest. Add the melted butter and stir until the mixture forms pea-size and slightly larger clumps. Refrigerate while making the filling.

For the filling: in a 9X13-inch dish combine the rhubarb, strawberries, lemon juice, sugar, corn-starch, and salt until well mixed. Let the mixture sit for 10-15 min (this will help the corn-starch dissolve in the liquid from the fruit which will help it thicken better while baking).

Spread the fruit filling evenly in the pan.

Remove the topping from the fridge and crumble it in your fingers if it has hardened while chilling. Cover the fruit filling evenly with the topping.

Place the 9X13-inch dish on a foil-lined pan (in case the crumble bubbles a bit while baking) and bake for 45-50 min until the fruit mixture is bubbling and the topping is golden brown in spots.

Let the crumble rest out of the oven for 15 min (the filling will thicken as it rests). Serve warm with vanilla ice cream.