Preheat oven to 425°F.

Line an edged baking sheet with parchment paper.

Unroll the pie crust onto the parchment paper.

In a small bowl, combine flour, sugar, corn starch, and salt.

Prepare apples by removing the cores, slicing the apples to quarter-inch slices, and adding them to a large bowl.

Add the lemon juice to the apples.

Cover the apples the the dry mixture and toss to coat the fruit.

Arrange the apples around the center of the pie crust, leaving about 1½ inches around the outside edge.

Fold the outside of the crust over in 8 sections to cover the edges of the fruit and pinch together any cracks.

Brush the exposed top of the crust with the beaten egg wash and sprinkle the crust with coarse sugar.

Sprinkle small pieces of butter on the top of the fruit.

Place the baking sheet in the oven for 25-30 minutes until the crust is golden brown.

Remove from the oven and let stand for 15 minutes to cool.