Best Mac and Cheese - for you Claudia :)

I found this recipe on cooks.com several years ago and have never used another mac and cheese recipe since. I brought out the recipe for my cooking class to try and they loved it. It is easy and fast to make. Good Stuff!!!!!

Macaroni and Cheese Recipe -
3 tbsp. butter
1/4 c. flour
1 tsp. salt
1/2 tsp. dry mustard
1/2 tsp. pepper
2 1/2 c. milk
2 1/2 cups Cheddar cheese, grated
1/2 lb. Velveeta cheese
1 cup Mozzarella cheese
1 (16 oz.) box elbow macaroni
1/2 tsp. paprika

In large saucepan, melt butter over low heat. Stir in flour, salt, mustard and pepper until smooth; take off heat. Half a cup at a time, stir in milk until smooth. Stir constantly for 10 minutes on low to medium heat until thick; take off heat. Stir in 2 cups Cheddar cheese, Velveeta cheese and Mozzarella cheese until melted. Put cooked macaroni in a 9 x 13 greased casserole dish, pour cheese mixture over and mix well. Sprinkle paprika and leftover Cheddar cheese on top. Bake at 375 degrees for 20 minutes.