Heat oven to 425 degrees.

Unroll pie crust and place on a baking sheet. You can use a Silpat or parchment paper, but I just put it straight onto the baking sheet and it did fine (no greasing of pan required).

In a medium sized bowl, toss together the blueberries, cornstarch, sugar and lemon juice.

Spoon mixture into the middle of the crust leaving about 2" around the edge.

Fold the edges over in a haphazard way (neatness does not count here). You want fruit in the middle to show.

Cut the butter up into 6-8 chunks and place on top of the blueberries.

Whisk up the egg and water in a small bowl. Brush this onto the crust and sprinkle with sugar.

Bake 20-23 minutes until the crust is a nice golden brown.

Once cooled, you can move it onto a serving plate or be all fancy and serve straight from the baking sheet.

This is especially yummy with a big scoop of vanilla ice cream on top of your slice.