Preheat the oven to 350, and lightly grease a pie plate with cooking spray.
Make the crust/roll out the crust on a lightly floured surface. Place into the pie plate.
In a mixing bowl, toss the strawberries, rhubarb, sugar, cornstarch, cinnamon, nutmeg and salt.
Pour the mixture into the pie plate. Make a lattice top over the strawberry mixture and pinch the edges together well.
Mix the egg yolk with 1 Tbsp water in a small mixing bowl and brush on top of the lattice and edges of the pie crust.
Bake in the preheated oven (on a foiled lined baking sheet) for 1 hour, 15 minutes.
Serve warm with ice cream, or cold (for breakfast!). Yes, it's OK to eat this for breakfast! ;)