Preheat the oven to 400 and ensure a rack is placed in the center position of the oven. Have ready an 8x8” baking dish or similar small capacity oven-safe baking dish.

Heat a cast iron skillet over medium-high heat until hot. You should be able to hold your hand a few inches from the surface for just a few seconds before it feels too hot! Turn the heat down to medium, add the olive oil and the beef.

Cook the beef while breaking it into crumbles every few minutes using with a wooden spoon. It’s important to take breaks from stirring the meat and really letting a golden brown crust form on the meat. This will take about 10 minutes.

When almost all of the meat is done, add the diced onion. Cook for 4-5 minutes, until the onion softens.

Next, add the garlic and tomato paste and cook for 1 minute while stirring.

Sprinkle the salt, pepper, beef broth, Worcestershire, soy sauce and the flour. Let cook for about 2 minutes to thicken, and then add the frozen veggies. Stir well to combine, and then turn off the heat—the residual heat will defrost the veggies.

Scrape the mixture into an 8x8” baking dish.

Wash the potatoes and prick them all over with a fork. Wrap each one in a paper towel, and microwave all of them for 10-12 minutes, until soft and cooked all the way throughout. You’ll have to insert a knife into the center to test for doneness of each potato.

Let the potatoes cool slightly, and then use the paper towel to peel off the potato skins.

In a bowl, mash the potatoes with the butter, milk and salt.Spread the potato mixture on top of the meat mixture in the baking dish.

Bake on the center rack of the oven for 25 minutes, or until the mixture is bubbling and the potatoes are starting to turn golden brown in several places.