In a large skillet over medium heat, brown the ground beef for about 5-7 minutes until fully cooked.

Add in the diced onion, potatoes, carrots, and celery, and cook for another 5 minutes until veggies soften.

Stir in the frozen peas and fresh thyme, adding any additional seasonings, then let simmer for about 10-15 minutes.

Remove from heat and let cool completely for about 15-20 minutes.

Preheat oven to 400°F (200°C) and roll out the puff pastry, cutting it into 4-6 inch squares.

Place a tablespoon of cooled filling in the center, fold over to seal, and press edges.

Brush the tops with egg wash and bake for 24-26 minutes until golden brown.

Let cool for about 5 minutes before serving warm.