Dijon-style mustard and roasted red sweet peppers update the classic tuna casserole recipe. Yet even a modern take on tuna noodle casserole needs something crunchy on top. As always, potato chips do the trick!
Preheat oven to 375 degrees F. In large saucepan cook noodles according to package directions. Drain; return noodles to pan.
For sauce, in medium saucepan cook celery and onion in hot butter until tender. Stir in flour, mustard, and 1/4 teaspoon black pepper. Add milk all at once; cook and stir until slightly thickened and bubbly, whisking to remove any lumps.
Gently fold sauce, tuna, and peppers into noodles. Transfer to lightly greased 1-1/2-quart baking dish. Top with chips. Bake, uncovered, 30 to 35 minutes or until heated through. Let stand 5 minutes. Serves 4.