1. In large nonstick skillet melt 1 tablespoon butter. Stir in SUNSHINE CHEEZ-IT Original snack crackers and Parmesan cheese. Cook, stirring constantly, over medium heat for 6 to 7 minutes or until crispy and lightly browned. Remove from heat. Set aside.
2. In large saucepan melt the 1/4 cup unsalted butter. Stir in flour. Cook, stirring frequently, over medium-low heat for 5 minutes. Increase heat to medium-high. Gradually whisk in milk and half-and-half. Continue cooking, stirring constantly, until mixture simmers and slightly thickens. Stir in salt, mustard, thyme, red pepper and nutmeg. Reduce heat to low. Cook, uncovered, for 10 minutes, stirring frequently.
3. Meanwhile, cook macaroni according to package directions. Drain well.
4. Remove milk mixture from heat. Add cheddar cheese and Gruyère cheese, a little at a time, stirring until melted after each addition. (If necessary, return saucepan to very low heat. Cook and stir until cheese melts.) Fold in macaroni. Ladle into serving bowls. Sprinkle cracker mixture on top.