In a large sauce pot over medium heat, add the fresh diced strawberries and granulated sugar. Cook for 10-12 minutes until most juices have been released and liquids start to rapidly boil, stirring often.

In a small bowl, whisk together fresh lemon juice and cornstarch until smooth to create a slurry.

Slowly pour the cornstarch slurry into the boiling strawberries while whisking constantly. Cook for another 1-2 minutes until the mixture is thick and glossy.

Remove from heat, stir in vanilla extract, and transfer filling to a bowl to cool for 30 minutes.

Adjust oven racks and preheat to 375°F. Place a 9 inch pie dish onto a large rimmed baking sheet.

Remove refrigerated pie crusts from packaging and unroll. Place one crust in the bottom of the pie dish, pressing it against the sides. Save the second crust for the top.

Whisk the egg in a small bowl to create an egg wash for the pie crust.

Brush the bottom and sides of the pie crust with the egg wash and set aside the remaining egg wash for the top crust.

Pour the slightly warm strawberry filling into the prepared pie crust.

Place the second pie crust on top, trim excess crust from the edges and crimp edges to seal.

Brush the top surface of the pie with the egg wash and cut 4-1 inch slits into the top crust.

Bake for 40-45 minutes or until the crust is golden brown. Allow to cool completely for at least 5-6 hours.

To make the glaze, whisk powdered sugar, 2 tablespoons whole milk, and vanilla extract until smooth. Adjust consistency with more milk if needed.

Spread the glaze over the cooled pie and sprinkle with rainbow sanding sugar. Allow to set for at least 30 minutes before slicing.