Boil water in a large saucepan. Add ½ tsp salt and pasta; stir. Cook until pasta is al dente’. Drain and rinse with cold water; set aside. Melt 3 Tbsp butter in saucepan and stir in flour and 1 tsp salt. Cook, stirring constantly, 2 minutes; slowly add milk. Whisk until smooth; gently bring to a simmer. Reduce heat; add 1 cup cheese. Stir until smooth. Meanwhile, sauté mushrooms, garlic and leek in remaining 1 Tbsp butter. Add to cheese sauce; set aside 1 cup for Broccoli Cheese Bakers. Add remaining sauce to cooked pasta and mix. Transfer pasta to a baking dish. Top with remaining cheese and bake at 350°F 15-20 minutes, until golden brown.

Steam green beans in salted water, 10 minutes or to desired finish.

Tip: To clean leek, cut in half lengthwise and rinse between each ring. Save for later: 1 cup cheese sauce for Broccoli Cheese Bakers