Preheat your oven to 375°F (190°C).

If using a frozen pie crust, remove from the freezer and line with parchment paper, then fill with pie weights or beans and bake for 15 minutes. Remove the pie weights or beans and cool for 15 minutes. (If using a refrigerated or homemade crust, Roll out the 9-inch pie crust and fit it into a pie pan. Trim and flute the edges as desired. Continue as directed above.)

In a large mixing bowl, combine the quartered strawberries, blueberries, granulated sugar, cornstarch, and lemon zest.

Gently toss until the berries are evenly coated. Let the mixture sit for 10-15 minutes to allow the juices to release.

Pour the berry filling into the prepared pie crust, spreading it evenly.

In a separate bowl, mix together the flour, brown sugar, rolled oats, and salt.

Pour the melted butter over the oats, then mix with a fork until the mixture becomes crumbly. If you want a flakier topping, use very cold butter cut into small pieces and gently work into the oats with a fork.

Sprinkle the crumb topping evenly over the fruit filling.

Place the pie on a baking sheet to catch any drips.

Bake for 45-50 minutes, or until the topping is golden brown and the filling is bubbly.

If the crust starts browning too quickly, loosely cover the edges with aluminum foil.

Remove the pie from the oven and let it cool for at least 2 hours before slicing. This allows the filling to set.

Serve warm or at room temperature with whipped cream or vanilla ice cream. Enjoy!