In a large bowl, whisk together the flour and salt.

Add the cold butter and shortening to the flour mixture. Using a pastry blender or your fingertips, cut the butter and shortening into the flour until the mixture resembles coarse crumbs, with small pieces still visible.

Gradually add the ice water, one tablespoon at a time, mixing gently after each addition until the dough just comes together.

Turn the dough out onto a lightly floured surface and form it into a disc. Wrap tightly in plastic wrap and refrigerate for at least 30 minutes, or up to 2 hours.

After chilling, remove the dough and let it sit for a few minutes to soften slightly. Roll out into a 12-inch circle on a floured surface.

Carefully transfer the dough to a 9-inch pie plate, pressing it into the bottom and up the sides. Trim excess dough and crimp the edges with fingers or a fork.

For a golden crust, brush the edges with a beaten egg and sprinkle turbinado sugar.

Place the prepared crust in the refrigerator or freezer to chill for at least 30 minutes.

In a large bowl, combine the rhubarb, strawberries, sugar, cornstarch, lemon juice, cinnamon, nutmeg, and salt, tossing gently to coat.

Let the mixture sit for about 15 minutes, allowing the juice to seep out.

Preheat your oven to 400°F (200°C).

Pour the strawberry-rhubarb filling into the chilled crust, spreading it evenly.

To prevent burning, cover the crust edges with a pie shield or aluminum foil.

Bake for 20 minutes at 400°F (200°C), then reduce the temperature to 375°F (190°C) for an additional 30-40 minutes, until the crust is golden and filling is bubbling.

Check if the pie is done by inserting a knife into the filling; it should be thick and not runny.

Remove from the oven and allow to cool completely on a wire rack.

Meanwhile, prepare the cream topping. Combine heavy cream, powdered sugar, and vanilla in a bowl.

Beat on medium-high speed until stiff peaks form.

Once cooled, spread the whipped cream over the pie or serve with dollops of cream.

Slice and serve immediately for the best experience, as the cream may soften over time.