1 pkg (16 oz.) elbow macaroni, 2 eggs, 1 can (12 oz.) evaporated milk, 1/4 cup butter, melted, 2 T. prepared mustard, 1 t. seasoned salt, 1 t. pepper, 8 oz. Velveeta cheese, melted, 2 cups (8 oz.) shredded mild cheddar cheese, divided, 2 cups (8 oz.) shredded sharp cheddar cheese, divided.
Cook macaroni according to package directions. Meanwhile in a large bowl, whisk the eggs, milk, butter, mustard, seasoned salt and pepper until combined. Stir in the processed cheese and 1 1/2 cups of each cheddar cheese. Drain macaroni.
Stir into cheese mixture. Pour into greased 3 qt. baking dish. Top with remaining cheese. Bake, uncovered at 350 degrees for 25 - 30 minutes or until cheese is melted and edges are bubbly.