Preheat oven to 375° F.
Clean rhubarb and remove strings and tough edges using a sharp knife or a potato peeler. I like using a knife best. Slice into 1/4-inch slices.
Clean strawberries and remove stems. Slice berries into 1/4-inch slices.
Add rhubarb and strawberries to a large mixing bowl. Blend brown sugar, cinnamon and cornstarch until integrated, and then gently toss it into the fruit mixture, making sure to coat the fruit well. Stir in 1/4-cup of the brown sugar crumb topping.
Pour filling mixture into the prepared pie shell.
Evenly distribute remaining Brown Sugar Crumb Topping (recipe above) over the top of the pie.
Bake pie for approximately 45-55 minutes, or until the top is turning golden-brown and fruit filling is bubbly. If the crust looks like it’s golden brown, but the filling isn’t yet bubbling, lay a piece of foil over the pie and continue to bake until the filing is bubbling.
Serve warm or cold with a big scoop of vanilla frozen yogurt or ice cream!