4cupsmashed potatoessee NOTES for recipe if you don't have leftovers
1cupgrated cheddar cheeseDIVIDED
Adjust oven rack to center position and preheat oven to 375°F.
Crumble beef into a large skillet and cook over medium-high heat until no longer pink; drain and discard grease. Season beef with oregano, salt, and pepper. Stir in the tomato paste, beef broth, and Worcestershire sauce. Add the carrots, mushrooms, and garlic and cook until vegetables are tender, about 10 minutes. Stir in the peas and corn and taste and adjust the seasonings.
Briefly warm the leftover mashed potatoes in the microwave so that they can be stirred until smooth (add a splash of milk, if necessary). Stir in 1/2 cup cheddar and spread the potatoes over the top of the meat/veggie mixture in the skillet. Sprinkle remaining 1/2 cup cheddar on top. Bake until potatoes and cheese are golden brown, about 30 to 40 minutes. Serve hot.
If desired, you may transfer the meat/veggie mixture to a 2-quart oval casserole dish (or similar sized dish) and top with mashed potatoes before baking.
TO MAKE MASHED POTATOES:(in case you don't have leftovers)
1 1/2 pounds potatoes, peeled & cubed
1 teaspoon salt
3/4 cups milk
4 tablespoons butter
Garlic salt, to taste
Freshly ground black pepper, to taste
Place the potatoes in a saucepan and cover with 1 inch of cold water. Stir in 1 teaspoon salt. Bring to a boil over high heat. Reduce heat to a simmer and cook for 8 to 10 minutes or until potatoes are tender but not mushy. While potatoes are cooking, microwave milk and butter until hot (or heat in a small saucepan). Once potatoes are done, drain water and return potatoes to pot. Pour hot milk/butter over potatoes and mash directly in pot. Season with garlic salt (or regular salt, if you prefer) and fresh pepper, to taste.