Set 4 to 6 quarts of salted water to boil for the macaroni. Add pasta when water boils and cook for 6 to 7 minutes until al dente. Remove from heat. Strain and return the pasta to a large mixing bowl. Add 2 TBS of butter. Stir & set aside.
Melt remaining 6 TBS of butter in a large saute pan. Slowly whisk in flour and continue stirring for 2 to 3 minutes until roux is smooth & golden. Slowly add warm milk and stir until silky in texture. Add in salt, white pepper and nutmeg. Remove from heat and slowly stir in 6 cups of Sargento 4 Cheese Mexican Mix. Keep stirring until cheese has all melted and sauce is thick.
Pour over pasta and begin to fold in black beans, green onions, chiles, avocados & cilantro. When well mixed, transfaer to a 13X9 glass baking dish.
Spoon up to 2 cups of salsa across the top in swirls or lines.
Bake for 30 to 35 minutes until top is beginning to brown or the sides are bubbling.
Let rest for a few minutes to settle before serving.
Can garnish with sour cream, hot sauce, more cilantro or more salsa