• Preheat the oven to 375 F.

Make pie crust

• Pulse flour and salt in the food processor.
• Then, add the cubes of butter little by little until they are integrated into the flour.
• Finally, add the milk. You want to reach a playdough consistency that is not too crumbly but not wet and sticky. Divide the dough into two disks and cover with plastic wrap. Place them in the refrigerator until you are ready to use them.

Make filling

• Place the diced strawberries and rhubarb in a large mixing bowl. Add sugar, arrowroot starch, lemon juice, and cinnamon. Mix and set aside.

Assemble

• Remove the pie crust from the fridge. Place one disk of the dough between two pieces of parchment paper and use a roller to smooth it out. If the dough is too hard, roll it around with your hands to soften it. Place it inside a 9-inch pie plate. Place the prepared pie plate into the oven for 5 minutes to harden a bit, then let it cool for 5 minutes before filling.
• Add the filling to the pie plate.
• Smooth out the second dough disk and place it over the pie plate. Pinch and seal the edges of the pie with your thumbs of a fork. Use a small knife to make vent holes for the pie.
• Then, use any extra pie crust to decorate the edges of the pie.
• Finally, mix the egg and water. With a silicone brush, apply the egg wash to the top of the pie.
• Bake in the oven for 40 minutes or until the crust is golden.
• Remove from the oven and serve with a side of vanilla ice cream.