Macaroni and cheese with vegetables

This is more interesting than the mac and cheese we ate as kids. And it’s versatile — add other vegetables of your choice when sauteing the bell pepper and mushrooms. This dish is best when made just before serving.
8 ounces pasta (such as bow ties or large ribbed macaroni)
3 tablespoons butter
1 tablespoon all-purpose flour
½ cup vegetable or chicken stock
¾ cup milk
½ cup finely shredded cheddar cheese
½ cup freshly grated parmesan cheese
1 cup minced fresh flat-leaf parsley
1 tablespoon minced fresh basil or1 teaspoon dried basil
¼ teaspoon paprika
¼ teaspoon freshly ground pepper, or to taste
Dash of salt, or to taste
2 cups broccoli florets
1 red bell pepper, coarsely chopped
1 cup sliced mushrooms
2 scallions, coarsely chopped
Bring a large pot of salted water to a boil; cook the macaroni according to package instructions or until al dente.
While the macaroni is cooking, melt 2 tablespoons of the butter in a medium saucepan. Remove from the heat; add the flour and stir until smooth. Whisk in the stock and milk, stirring over medium heat until the mixture thickens. Reduce the heat to low; stir in the cheeses and seasonings. Continue stirring until the cheeses melt. Remove from the heat and set aside.
Melt the remaining butter in a large nonstick skillet. Add the remaining ingredients. Cook stirring constantly, until the vegetables are crisp-tender, about 5 minutes. Reduce the heat to low.
When the noodles are done, drain well. Toss with the vegetables. Stir in the cheese sauce. Taste and adjust the seasoning.