1. Defrost spinach. Remove the spinach from the freezer several hours before you plan on cooking. It will defrost faster if you cut it into smaller pieces after it has defrosted some. Use a sharp knife. When it has completely defrosted, squeeze the spinach with your hands to get rid of all excess water. Chop spinach.
2. Make mashed potatoes. Peel and cut the potatoes in about 1 inch slices. Place in a large pot and cover with cold water. Add 1 teaspoon salt. Bring to a low boil on medium heat. Cook potatoes until very tender - 20 to 25 minutes. Remove from heat and drain. Mash the potatoes with a potato masher or process in a food mill. Stir in milk and butter and season to taste with salt and pepper. Set aside. (If you are using packaged mashed potatoes or if you have leftovers, you will need 6 cups of mashed potatoes for this recipe.)
3. Preheat oven to 400°F (200°C).
4. Cook onions and bacon. Peel and chop the onions. Slice the bacon in small pieces. Heat the olive oil in a large skillet on medium heat. Add the onions and bacon and cook, stirring occasionally, until the onions are quite soft and the bacon cooked - about 8 minutes.
5. Add garlic and meat. Peel and crush the garlic and add it to the onions and bacon. Cook for one minute. Add the ground beef and cook, stirring occasionally, until the meat is cooked through, about 5 minutes.
6. Add tomatoes and seasoning. Slice and seed the tomatoes, then dice them. When the meat has cooked, add the diced tomato, chopped spinach, Parmesan cheese, herbs de Provence, salt, pepper and cayenne pepper. Stir to combine well and remove from heat.
7. Assemble. Lightly oil a 13X9 inch baking dish. Spread half of the mashed potatoes in the bottom of the dish. Top with all of the meat mixture, spreading it evenly. Top with the remaining mashed potatoes and then the grated cheese.
8. Bake at 400°F (200°C) for 30 minutes or until lightly browned. Remove from oven and allow to cool 5 minutes before serving.

Makes 6 - 8 servings.

Serving Suggestion: Serve with a simple salad of mixed greens topped with olive oil and balsamic vinegar.