For an extra layer of flavor, consider browning the ground beef with a tablespoon of olive oil. To prevent the mashed potatoes from drying out, you can drizzle a little melted butter or milk over the top before the final 20-minute cook time. Feel free to customize the vegetables with your favorites! Peas, carrots, and corn are classic choices, but green beans or mushrooms would also be delicious additions. If you don't have tapioca, you can substitute cornstarch as a thickening agent. Mix it with a little cold water before adding it to the broth mixture to prevent clumping.