2. In a small bowl combine the crackers, melted butter, lemon juice, salt, and pepper; set aside.
3. Bring a large saucepan of water to a boil. Add the pasta and cook, stirring occasionally, for 8 minutes or until the pasta is not quite tender (it will cook more later). Drain into a colander; shake well. Transfer to a bowl and toss with the olive oil; set aside.
4. In a large flameproof casserole over medium heat, melt the 1 tablespoon of butter. Slowly whisk in the flour. Continue to cook for 1 minute or until lightly colored. Gradually whisk in the cream and milk, whisking constantly to prevent lumps from forming.
5. Stir in the mustard and remove from the heat. Fold in the pasta, fontina, and Worcestershire. Transfer the mixture to the baking dish. Sprinkle with cheddar and the cracker mixture.
6. Bake the pasta for 25 minutes or until the top is brown and the dish is bubbling at the edges. Adapted from Zon's