Shepherd's Pie

Ingredients

• 1 large onion, chopped
• 2 tablespoons butter
• 2 -3 cups diced leftover beef
• 2 cups gravy, leftover canned or 2 cups gravy, prepared from a mix
• 12 cup frozen carrots, cooked
• 1 cup frozen peas, cooked (or use a bag of mixed peas and carrots)
• salt and pepper
• 1 egg
• 2 cups leftover mashed potatoes or 2 cups prepared instant mashed potatoes