French Meat Pie

Ingredients

• 2 Tbsp. cooking oil
• 1 1/2 large onions, thinly sliced
• 1 lb. ground lean beef
• 1 lb. ground lean pork
• 1 c. mashed potatoes
• 1 tsp. salt or to taste
• 1/4 tsp. pepper
• 2 tsp. ground allspice or to taste
• 1 (9-inch) pastry for double crust pie
• 1 egg, beaten (optional)