Prepare mashed potatoes: Place potatoes in a pot with enough water to cover by about 1/2 inch. Cook until potatoes are tender. Pour off cooking water (or save. Simmer ground beef, onion and steak sauce then spoon it into a dish for this Cheesy Potato Pie. Top it with mashed potatoes for a hearty Cheesy Potato Pie. Homemade stew in 20 minutes! Try a family-pleasing, comfort food meal that fits your busy schedule.