Easy Mini Chicken Pot Pies

Ingredients
For the Filling:
2 cups cooked chicken, shredded or diced
1 cup frozen mixed vegetables (peas, carrots, corn, etc.)
1/3 cup onion, diced
2 tablespoons butter
2 tablespoons all-purpose flour
1 cup chicken broth
1/2 cup milk
Salt and black pepper, to taste
1/2 teaspoon garlic powder (optional)
For the Crust:
1 package refrigerated pie crusts (or puff pastry), thawed
1 egg, beaten (for egg wash)
Instructions