Rinse cherries, then pat dry with a paper towel.

Pit cherries, and cut in half with your fingers or a knife.

Next, prepare the cheese mixture by stirring together cream cheese, powdered sugar, and vanilla extract. Note: taste your fruit to see how sweet it is. If your cherries are quite tart, you may want to add more powdered sugar to your cream cheese mixture.

Make egg wash by whisking together one egg with a tablespoon of cold water and a pinch of salt.

Remove puff pastry dough from the refrigerator. Flour your counter or a large cutting board.

Place a dollop of cheese mixture (about 1 tablespoon) into the center of each pastry square.

Top with a few cherry halves (about 3-4), then paint a small amount of egg wash on one corner of the pastry square as you bring it up and over the opposite corner and squeeze together tightly to seal. Don’t worry if edges become unsealed during baking—the point is just to make sure the filling stays inside the pastries as they bake. Put egg wash in the refrigerator—you will need it again later.

Next, you need to chill the pastries before baking. If you have a sheet pan that will fit in your freezer, line it with parchment paper and carefully place the pastries on it before moving it into the freezer. If a sheet pan won’t fit, line a plate with parchment paper, and place the pastries on that. Freeze pastries for at least 30 minutes, until they are quite firm.

Preheat oven to 210 degrees Celsius or 400 degrees Fahrenheit. After at least 30 minutes in the freezer, place pastries a couple of inches apart on a parchment paper-lined sheet pan (if they are not already on one).

Then paint all exposed pastry with egg wash using a pastry brush.

Bake for 25 minutes, until pastries are cooked through and golden brown.

Sprinkle with powdered sugar to serve, if you like.