Preheat your oven to 400 degrees F.

Remove frozen pie crust from freezer to thaw out

In a medium bowl, combine rhubarb, strawberries, brown sugar, white sugar, flour, lemon juice, and salt. Mix with a spoon until evenly combined. Set aside.

Next, prepare the crumble topping. In a bowl, mix together the butter, flour, brown sugar, quick oats, and cinnamon. I find using your hands works best. Mix until crumbly.

With a fork, poke holes into the bottom and sides of your pie crust

Fill the dough with the strawberry rhubarb mixture leveling off the top. Then, sprinkle evenly with the crumble topping.

Bake the pie for 20 minutes at 400 degrees F. Then, reduce the temperature to 350 degrees and continue baking for 35 to 45 minutes. You'll know the pie is done when the filling is bubbling and the top is browned.

Let the pie to cool for at least two hours before serving. This will allow the filling to set. serve with a scoop of vanilla ice cream if you'd like.