You can also use the manicotti shells in this. I use the Jumbo sea shells because I think they're easier to stuff, they don't seem to break and tear as easily as manicotti. The tomato sauce and cream sauce swirl together when it is served and oh my, it really is delicious!
1Cook Canneloni shells according to package directions; drain and set aside.
Combine tomato sauce and 3 Tbsp. parmesan cheese in a small saucepan; cook over medium heat, stirring constantly until mixture is heated. Spread 1 cup tomato mixture in a lightly greased 9x13 inch baking dish. Set aside remaining sauce.
2Saute onion and garlic in olive oil in a large skillet until tender. Add spinach; cook, stirring often until the spinach is just tender. Remove spinach mixture, and set aside.
3In a separate pan cook ground beef over medium heat until brown, stirring to crumble; drain. Discard drippings from skillet. Add spinach, 1/3 cup parmesan cheese, 2 Tbsp. whipping cream, eggs, and oregano; mix well. Stuff cannelloni shells with ground beef mixture and place on tomato mixture in baking dish; Sprinkle each shell with fresh parsley and top with Mozzarella cheese dividing evenly over each shell. set aside.
4Melt 1/4 cup plus 2 Tbsp. butter in a heavy saucepan over low heat; add flour, stirring until smooth. Cook 1 minute and add 1 cup milk and whipping cream; cook over medium heat, stirring constantly until mixture is thickened and bubbly. Stir in pepper. Pour over cannelloni. Spoon remaining tomato mixture over cream sauce. Dot with 2 Tbsp. butter. Bake uncovered at 375 degrees for 25 minutes. Yield 6 servings.