Freezer Friendly: Cheddar-Beef Pastry Pockets

So.
I have been loving the Taste of Home magazine I bought.  I'm starting to think that I should batch cook once a month and then eat the fruits of my labour over the following month.  Or, batch cook over a week, doing what I've done this month making half and eating half.  I'm going to need to look through the magazine for what else I need to try.
I have a habit of making a roast and usually end up freezing the heel, figuring that I'll come up with something to do with it eventually.  I finally emptied all the ziploc bags out of the top of my freezer to figure out what exactly I'd been saving for "eventually".  Leftover grilled pork tenderloin becomes pork fried rice.  Leftover ham goes into frittatas.  But leftover roast beef?  I've never been sure what to do with it.
Enter this recipe.  Leftover roast makes so much more sense than buying a refrigerated roast au jus, discarding/finding another use for the jus, and chopping up the roast.  I also switched out the cheese for one I buy more often, and changed the vegetables for ones I eat.  Let's say that the inspiration came from Taste of Home.
Either way, we enjoyed these.  I present to you now Cheddar-Beef Pastry Pockets:

Ingredients:
1 Tbsp butter
1 small onion, finely chopped
1 stalk celery, finely chopped
1 carrot, finely chopped
1/4 c beef broth
2 cloves garlic, minced
6 oz cooked beef roast, diced small
salt and pepper, to taste
1 pkg frozen puff pastry, defrosted
6 slices cheddar cheese
1 egg
1 tsp water
Method:
1.  In a skillet, melt butter and add onion and garlic.  Cook, stirring occasionally, until soft.  Add celery and carrot, sauteeing until fragrant.  If the onion starts to brown, add broth in small amounts to continue to cook the carrots and celery.  Keep moisture to a minimum.  Add and stir the beef.  Heat the mixture through, then remove from heat.
2.  On a well floured pastry sheet, roll out puff pastry to a 9x15" rectangle.  Cut into 3 rectangles approx 9x15".  On one half of the pastry, place a slice of cheese.  Top with 1/6 of the beef mixture, leaving a border of pastry.
3.  Beat egg with water. Brush egg on the border of the pastry.  Fold pastry over the filling, and press the edges together with a fork.  (If freezing, place on a waxed paper lined baking sheet, and freeze until firm before wrapping in waxed paper and freezing in a resealable bag.)
4.  Preheat oven to 400F.  Transfer pastries to a baking sheet and brush with egg.  Bake at 400F for 20 minutes, until golden and heated through.

Adapted from Taste of Home

I started with a classic vegetable mix, and knew that I needed it to be cooked, but not mushy.  I used the broth to keep it from burning or browning too much.

I'd never worked with puff pastry before.  I will admit that I don't want to work with it in summer again.  I defrosted on the counter, as per the directions.  It probably set out a little longer than it should have.  The parchment paper the pastry was rolled in stuck to the pastry.  I swore.  A lot.  Thankfully, the rectangle was almost the prescribed size.  It may not look like it, but I used real cheese.  Processed slices would be icky.

Getting these off the pastry sheet was not as much of a challenge as I was afraid it would be.  The most awkward part was doing the fork pressing around the first 2 pieces on the pastry sheet, because of the piece of pastry on the one side.  But they went together reasonably quickly.

And isn't the final product pretty?  2 more meals in the freezer, ftw!