New Tuna Casserole

Directions

1. 1
   Preheat oven to 35
2. 2
   Prepare pasta according to package directions.
3. 3
   Meanwhile, cook green beans in boiling salted water to cover 30 seconds to 1 minute or until crisp-tender; drain. Plunge into ice water to stop the cooking process; drain.
4. 4
   Melt 2 Tbsp. butter in a large skillet over medium-high heat.
5. 5
   Add leeks, and saut 2 minutes; add mushrooms, and saut 5 minutes or until lightly browned.
6. 6
   Transfer leek mixture to a small bowl. Wipe skillet clean.
7. 7
   Melt 4 Tbsp. butter in skillet over medium heat; whisk in flour, and cook, whisking constantly, 2 minutes. Gradually whisk in cream and broth. Bring mixture to a boil, stirring often. Reduce heat to medium-low; gradually whisk in Cheddar cheese and 4 Tbsp. Parmesan cheese until smooth. Stir in salt and pepper.
8. 8
   Stir cream mixture into pasta. Stir in tuna, next 2 ingredients, beans, and leek mixture; transfer to a lightly greased 13- x 9-inch baking dish.
9. 9
   Stir together potato chips, next 2 ingredients, and remaining 2 Tbsp. Parmesan cheese in a small bowl; sprinkle over pasta mixture.
10. 10
    Bake at 350 for 35 to 40 minutes or until bubbly.
11. 11
    Let stand 5 minutes before serving.