1 Melt The Butter In A Medium Pot On Medium Heat And Add The Can Of Tomatoes, Including The Juice. If You Are Using Whole Canned Tomatoes (Or Fresh Ones) Crush Them With Your (Clean) Fingers As You Put Them In The Pot. Simmer Gently, Partially Covered, For 30 Minutes. 2 Once The Sauce Is Cooking, Heat A Large Pot Of Well Salted Water To A Strong Boil. Add The Shell Pasta To The Boiling Water And Cook At A Vigorous Boil, Uncovered, Until Al Dente, Cooked Through But Still A Bit Firm To The Bite, Which Is Usually Whatever The Time Specified On The Pasta Package Minus About 2 Minutes. Drain And Set Aside. 3 Pour Off The Excess Oil From The Tuna Can And Stir The Tuna Into The Tomato Sauce. Add The Ricotta Cheese, And Add Salt To Taste. Turn Off The Heat. Mix The Sauce With The Pasta In A Large Bowl. Mix In The Basil. 4 Pour The Pasta Into A 2 To 3-Quart Casserole Dish And Top With The Parmesan Cheese. Put Under A Hot Broiler For 4-6 Minutes, Until The Cheese Is Melted And Lightly Browned. Serve Hot.