Pre-heat oven to 350°F. In a medium pot, cook noodles according to package instructions.
While noodles are cooking, prepare the cheese sauce. Heat 4 tablespoon of salted butter. Once melted whisk in the flour till thick. Slowly add the milk, whisking between each cup, and then whisk in the ale. Add the cheese and whisk till melted. Add salt, pepper, and green onions and gently whisk.
Drain the pasta and add it to the cheese sauce. Gently stir to fold the noodles into the sauce. Pour pasta into an oven safe baking dish (9x13 will work well, or a 12-inch round baking dish).
Stir the breadcrumbs, melted butter, and parsley together. Top mac and cheese with breadcrumb mixture. Bake uncovered for 20 minutes.