Strawberry rhubarb crumble bars

Ingredients

• Crumble mixture
• 1 cup 3 plus tablespoons unsalted butter, chilled from the fridge
• 2 ½ cups (390 g) all-purpose flour
• ¾ cup (95 g) graham cracker crumbs
• ½ cup plus 2 tablespoons (62 g) large flake oats
• ½ cup (105 g) sugar
• ¾ cup (144 g) brown sugar, packed
• 1/8 teaspoon salt
• Zest of one lemon
• 1 egg; 1 egg white
• 3 cups rhubarb sliced into 1-cm pieces
• 3 cups strawberries halved and then sliced
• 2 teaspoons vanilla
• 1 tablespoon plus 2 teaspoons corn starch
• recipeIngredient ends