Creamy Stove Top Mac And Cheese Recipe

Name: Creamy Stove Top Mac And Cheese Recipe
Ingredients: 1lb elbow macaroni or similar pasta(shells and rotini work well); 1 small or 1/2 large onion, very finely diced; 1 stick butter; 3 1/2-4 cups milk(+/-); 1/2 cup flour; 1 1/2t dry mustard; 4-6oz cream cheese, softened, or even warmed in microwave(you want no chill on this at all); 4-5 cups of various cheeses, shredded*(there is no right or wrong, here, it's all to taste...personally, i like to use a majority sharp cheddar cus i like the sharpness it brings to the finished dish, but other than that, be creative!); Salt and pepper; Dash of hot sauce