Boil the lasagna and set aside.
Cook the meat adding the tomatoes, garlic, onion, pimento, tomato paste, pepper to taste and salt.
Make the White Sauce: Over a low flame, melt the butter, stir in the flour, and add the milk and black pepper.
Mix, preferably with a fork to ensure that the flour don't lump together. Continue to boil until the milk gets thick. Remove immediately from the flame.
Place a layer of white sauce on a lasagna. Then add a layer of meat and top with cheese. Now roll the lasagna and place it seam side down in a greased baking dish. (The one we used was 12 x 8 x 2 inches). Sprinkle with cheese.
Preheat oven to 450 degrees F. Cover the top with foil and bake for 20 minutes then remove the foil and bake for10 minutes longer or until the cheese looks golden.