• 1 cup all purpose flour
• 2/3 cup sugar
• 1/2 cup cold butter cut in pieces
• 1 Tbsp vanilla bean paste
• 1 1/4 cup sugar
• 1/3 cup flour
• 1 Tbsp cornstarch optional
• 2 cups thin sliced rhubarb
• 2 cups sliced strawberries
• 1 apple peeled and grated (about 1/2 cup)
• Preheat the oven to 375F
• Put the crumble ingredients in a food processor and pulse about 25 times, or until it resembles coarse crumbs. Pour it into a bowl, add the vanilla paste, and work it in with your fingers, I like to create some clumps in the mixture with my fingers by pressing it together to get a coarser crumble texture.
• Whisk together the sugar and flour for the filling in a large bowl. Add the fruit and toss to get it all coated with the flour sugar mixture.
• Transfer your frozen pie crust to one of your own pie plates if you like. Fill the frozen pie crust with the fruit filling. Top with the crumble topping.
• Put the pie on a baking sheet and bake for 50-60 minutes until golden and bubbling. Check the pie half way through and if it seems to be browning too quickly, lay a piece of foil loosely over the top.