• ½ cup butter 

• ½ cup unbleached white flour

• 1 quart milk, heated

• 1 1/2 tablespoons Dijon mustard

• pinch of nutmeg

• salt and black pepper to taste

• ¼ cup vegetable oil 

• 4 cups chopped onions 

• 3 garlic cloves, minced or pressed 

• ½ cup fresh basil, chopped (2 teaspoons dried)

• 1 large head of cauliflower, cut in florets

• 6 ripe tomatoes, chopped or 3 cups canned tomatoes, drained and chopped

• 3 tablespoons fresh lemon juice
  

• 1 pound medium pasta shells 

• 1 cup freshly grated Parmesan cheese 

• 1 ½ cups shredded mozzarella or mild provolone cheese (6 ounces) 

• seasoned bread crumbs
  

To prepare the Bechamel sauce, melt the butter in a heavy saucepan on medium heat.  Sprinkle in the flour, whisking or stirring constantly, until a smooth paste is formed.  Add the heated milk slowly, a cup at a time, continuing to whisk until the sauce begins to thicken.  Add mustard, nutmeg, salt, and pepper and let the sauce thicken further on low heat.  Remove from heat and cover.

Saute the onions, garlic, and basil in oil.  When the onions are translucent, add the cauliflower and saute for 5 more minutes.  Add the tomatoes and simmer until the cauliflower is tender.

Cook the pasta a dente and then drain

In a large bowl, combine the cooked pasta, the sauteed vegetables, and the lemon juice.  Mix in the Bechamel sauce.  Put half of the pasta mixture in an oiled baking dish.  Sprinkle on half of each of the cheeses.  Add the rest of the pasta mixture and then the rest of the cheese.  Top with seasoned breadcrumbs and bake covered at 375 degrees for about 30 minutes and then uncovered for about 15 minutes  or until bubbling and golden on top.