Ham and Cheese Puff Pastry Slab Pie

Ingredients

• 2 sheets puff pastry , defrosted and rolled into 10-inch squares
• 1 tablespoon Dijon mustard (Smooth or grainy, your preference)
• 6 ounces shredded Emmental swiss cheese
• 4 ounces thinly-sliced ham (I use Black Forest or Virginia)
• ⅓ cup caramelized onions
• 1 teaspoon chopped thyme leaves
• 1 large egg
• 1 tablespoon milk
• ¼ teaspoon garlic powder
• 1 tablespoon chopped fresh parsley

Instructions

1. Preheat oven to 400 degrees F. Line a baking sheet with parchment paper.
2. Place one piece of puff pastry onto the baking sheet and spread with mustard, leaving a ½-inch border.
3. Sprinkle half of the shredded cheese over the mustard. Layer ham slices over the cheese, followed by the caramelized onions, thyme, and remaining cheese. 
4. In a small bowl, whisk together egg, milk, garlic powder, and parsley. 
5. Lightly brush the border of the puff pastry with the egg wash. Place the second square of puff pastry over the top and press the edges to seal.
6. Brush a ½-inch border on the top sheet of puff pastry with egg wash. Fold bottom edge of puff pastry over to create a crust of double thickness. Crimp edges with a fork. 
7. Brush top of puff pastry with egg mixture (you won’t use the entire amount). Cut three, 1- to 2-inch slits in the center of the pie to allow steam to escape while baking.
8. Bake for 25 minutes, until puffed and golden. Let stand for 10 minutes before slicing into squares or strips and serving.