This is a take from Ellie Kreiger's recipe form FoodTV. It's great for leftovers for lunch too!
1 pound lean ground beef (90 percent lean or higher)
2 teaspoons olive oil
2 medium onions, chopped (about 3 cups)
1 pound white mushrooms, sliced
10 oz defrosted chopped spinach
10 oz defrosted broccoli florets
2 teaspoons chopped fresh thyme leaves or 1 teaspoon dried
low-sodium beef broth (1/4 cup or more)
1 teaspoon salt
Freshly ground black pepper
2 heads (or 4 bags frozen) cauliflower, cut into florets
2/3 cup 1 percent lowfat milk
2 tablespoons margarine
Preheat oven to 350 degrees.
In a large nonstick skillet cook the meat over medium heat, stirring occasionally, until brown, about 5 minutes. Transfer the meat to a plate. Drain any fat remaining in the skillet.
Heat the oil in the skillet over a medium heat. Add the onions until the vegetables begin to soften, about 8 minutes. Raise the heat to moderately-high. Add the mushrooms and thyme and cook, uncovered and stirring occasionally, until the mushrooms are soft and their liquid has evaporated, about 8 minutes longer. Return the meat to the pan. Stir in some broth, but not too much that's it is too soupy. You aren't using flour here but want a "sauce." Add 1/2 teaspoon of the salt and 1/8 teaspoon of pepper and bring to a simmer being sure to scrape up any brown bits from the bottom of the pan. Stir in the broccoli and spinach. Pour the mixture into a 12-cup shallow baking dish (about 11 by 9 inches).
Steam cauliflower for about 15 minutes longer. Mash them with a potato masher until smooth, adding the milk, butter, the remaining 1/2 teaspoon of salt and a pinch of pepper and stir into the potato mixture.
Spread the "potato" mixture on top of the meat and bake until heated through, about 25 minutes.
This should make about 6 servings