Instructions

1. First, make the pie crust. Add the flour, granulated sugar, and salt to a food processor and pulse to combine. Add the butter cubes and pulse until the mixture resembles wet sand and no chunks of butter remain, about 20 seconds.
2. Add 3 tablespoons of the ice water (or vodka), then pulse until a dough begins to form a ball around the blade, about 20 seconds. If your dough doesn’t come together, add another tablespoon of liquid and pulse again.
3. Turn the dough out onto a clean work surface and divide it into two equal pieces. Flatten each piece into a 1-inch-thick oval disc, then wrap in plastic wrap. Refrigerate for at least 30 minutes (and up to 2 days).
4. Next, make the strawberry rhubarb filling. In a large pot over medium heat, add 1 cup of the strawberries, 1 cup of the rhubarb and 1/4 cup of the granulated sugar. Cook down the fruit, stirring constantly, until the fruit is fully broken down and reduced to a jammy consistency, about 8 minutes.
5. Remove from the heat and transfer the cooked fruit into a large mixing bowl. Add the rest of the strawberries and rhubarb, along with the remaining 1/2 cup of granulated sugar, cornstarch, vanilla, orange zest and salt. Use a silicone spatula to stir together until everything is evenly coated and no streaks of cornstarch remain. This combination of cooked and fresh fruit will prevent the filling from getting soupy.
6. Assemble the pie. Remove both dough discs from the fridge and set on the counter to soften for 5 minutes. Lightly dust a clean work surface with flour, unwrap one dough disc, and place it onto the surface. Dust with more flour and use a rolling pin to roll out the dough into a roughly 12-inch circle, dusting the top and underside with more flour as needed. Carefully roll up the dough around your rolling pin like a scroll, then drape it into a 9-inch pie pan. Press the dough into the bottom and sides of the pie dish, then use scissors to trim around the edges of the pie crust, leaving a ½ inch overhang.
7. Pour the filling into the pie pan, then set aside while you roll out the second dough disc to the same size and thickness. Place the second pie crust over the filling, letting the overhang hang off the sides to match up with the bottom crust.
8. Pinch the two crusts together to seal. Roll the excess dough on the edges in and under towards the dish, like you’re rolling up sleeping bag. Lightly squeeze the edges together sealing it in place. Use your index finger on one hand and your peace fingers on the other hand to create a crimp around the edge of the pie.
9. Use a sharp knife to cut vents into the top of the pie. This is essential so the pie is able to release steam.
10. In a small bowl, whisk the egg with 2 tablespoons of water. Use a pastry brush to brush the top of the pie with the egg wash. Sprinkle with demerara sugar all over. Place the pie into the freezer to chill while the oven preheats (this will keep the pie dough from becoming too soft at room temperature).
11. Preheat the oven to 375°F. Once the oven reaches 375°F, remove the pie from the freezer and place on a baking sheet lined with parchment paper (in case it drips!). Bake until the crust is golden brown all over and the filling has started to bubble, about 1 hour. Remove the pie from the oven and allow it to cool on a cooling rack for at least 2 hours, then serve.