Strawberry Rhubarb Crumb Bars

Preheat oven to 375°F. Grease a 9x13 inch baking dish and line with parchment paper.
In a large bowl, combine the flour, sugar, brown sugar, baking powder, salt and orange/lemon zest.
3 cups (360 grams) all-purpose flour, ¼ cup (50 grams) granulated sugar, ½ cup (105 grams) packed light or dark brown sugar,1 teaspoon baking powder, ¼ teaspoon salt, 1 tablespoon orange or lemon zest
Add the butter and use a fork or a pastry blender to cut the butter into the dry ingredients until the pieces are about the size of peas.
1 cup (226 grams) salted butter
Add the beaten egg and continue to blend until combined and mixture can be clumped together with your hand (but it will still be very dry and crumbly). Press half of the crumb mixture evenly into the bottom of the prepared pan.
1 large egg
In another bowl, toss together the strawberries, rhubarb, cornstarch and sugar. Dump on top of the crumb base, spreading it out evenly as needed. Use your hands to clump the remaining crumb mixture together and sprinkle evenly over the strawberry rhubarb filling.
3 cups (400 grams) sliced strawberries, 2 cups (260 grams) sliced rhubarb, ½ cup (100 grams) granulated sugar, 4 teaspoons cornstarch
Bake until topping is golden brown and the fruit is bubbling, about 50-60 minutes. Let cool completely before slicing, about 2-3 hours at room temperature or about 1 hour in the fridge. Or serve warm straight from the oven with vanilla ice cream.
For best results, store in the fridge, up to 5 days.