Thaw the puff pastry according to the package directions.

Trim the bottom inch or two from the asparagus. Put the asparagus and mushrooms in a bowl. Add olive oil, kosher salt, and pepper. Toss until evenly coated.

Roll the two pastry sheets on a lightly floured surface with a rolling pin, making them slightly thinner. Trim the edges with a sharp knife or pizza cutter so each sheet in an 8 inch square. Then cut each puff pastry square into fourths, so you will have 4 inch squares (8 total squares).

Note: Picture examples in post above.

In the center of each square spread some Boursin cheese, lay 2 or 3 pieces of asparagus and shiitake mushrooms, and some of the mozzarella. Fold two corners in, over top of the filling overlapping them slightly.

Place them on a lined baking sheet and brush the tops with the beaten egg. Sprinkle kosher salt over top.

Hint: If the puff pastry won't close you can stretch it slightly and also use some of the egg wash to hold it closed under the overlapped part. Try one first and If your first one won't close I suggest using the rolling pin to roll the remaining squares so they are thinner.

Place the baking sheet in a 400 degree oven for 14 to 16 minutes.