Preheat oven to 400°. Line a sheet pan with parchment paper.
Cut off some of the stem of the asparagus, I usually cut about .5 to 1 inch off depending on the stalk.
Melt the butter and stir in the grated garlic, ½ teaspoon of kosher salt, and ¼ tsp of black pepper. (if you want a little more spice, you can add the crushed red pepper to this mixture)
Generously coat and toss the asparagus in the garlic butter mixture.
Unfold the sheet of puff pastry so it lays flat on a clean surface. (there is no rolling required)
Cut the pastry in half horizontally and vertically so you have four pieces. Arrange them so they are sitting diagonally.
Lay a slice of cheese on each of the four pieces (the slices should be a little smaller, which is exactly what you want)
Lay five stalks of asparagus on each parcel. The stalks should be centered on the parcels to they stick out evenly top and bottom. The asparagus should also be arranged with a layer of three and a layer of two stacked on top.
Brush the part of the pastry that is exposed around the cheese with the beaten egg.
Then fold the side corners of the pastry squares over each other. Make sure to brush some of the beaten egg where the overlap, it'll act as glue.
Brush the outside of the pastries with the egg.
Sprinkle the remaining ¼ teaspoon of kosher salt on the pastry parcels.
Bake for 20 minutes at 400°.