For the filling:

1. Brown the ground beef with garlic and onion powders, an a generous pinch of salt and pepper. Drain any excess fat. Add onion, carrots, and celery to the pan and continue cooking over medium heat until the veggies are crisp-tender. Add tomato paste, beef broth, and Worcestershire sauce. Stir until the sauce is thick and the beef and veggie mixture is well coated. Taste and add salt and pepper as needed.
2. (If the sauce is far too thick, you can thin it with a little more beef broth. You don’t really want it very juicy or thin or it’ll be too soggy for the potato topping.)
3. Stir in the frozen peas and transfer the beef and veggie mixture to an 8×8″ (or 2 quart) baking dish.

For the mashed potato topping:

1. While the filling is cooking, boil the potatoes. Place the potatoes in a large pot and fill with water until the water is 1 inch above the potatoes. Bring the water to a boil over medium-high heat for 8-10 minutes, or until the potatoes are easily pierced with a fork. Drain potatoes. Return to the pan or a large bowl.
2. Pour in 1/2 cup water to start, the olive oil, and a very hefty dose of salt and pepper. Mash with a potato masher or blend with a hand mixer, or until potatoes are whipped and well blended, adding water as necessary to achieve your desired consistency. Try not to over blend them or they’ll get gluey.
3. Spread the mashed potatoes over the beef and veggie mixture. Rough up the surface a bit with a fork or spatula.
4. Bake at 375 degrees for 20-30 minutes or put under the broiler for 2-5 minutes, or until the potato topping is just starting to brown. (Those roughed up bits will get nice and toasty).