The only change I made was to add a little cream (actually half-and-half) to the beaten egg for the tops of the pastries. It just seemed like a good idea to me.
The turnovers are super simple to put together, and quite honestly I usually have most of the ingredients around the house. I'm excited about the note (below) that you can make these ahead and freeze them for 3 months--I might just do that when it gets closer to my parents visiting or something like that.
I think I baked them about 5 extra minutes to get them nice and golden brown.
Chicken and Gruyère Turnovers
Adapted from Real Simple
Hands-on Time: 15 minutes
Total Time: 40 minutes
1 1/2 cups shredded rotisserie chicken
1 1/2 cups grated Gruyère
1 cup frozen peas
2 sheets (one 17.25-ounce package) frozen puff pastry, thawed
1 large egg, beaten with 1 to 2 tablespoons half-and-half or heavy cream
1/4 cup Dijon mustard
1. Heat oven to 400° F. In a medium bowl, combine the chicken, Gruyère, and peas.
2. Cut the 2 sheets of puff pastry in half to form 4 rectangles and place on a baking sheet. Dividing evenly, top half of each rectangle with the chicken mixture. Fold over and seal the turnovers; brush the tops with the egg. Bake until golden, 20 to 25 minutes. Serve with the mustard.
*To make ahead, prepare the turnovers (but don’t bake them). Tightly wrap and freeze for up to 3 months. Let the turnovers thaw 20 minutes at room temperature before baking.