01 -
Bring a pot of water to a boil, add elbow noodles, and cook for 20 minutes, stirring often; drain thoroughly.
02 -
Melt butter in a large saucepan over medium heat. Whisk in flour to form a paste and cook for 60 seconds.
03 -
Gradually whisk in whole milk one cup at a time. Add paprika and continue whisking until the mixture thickens, about 2 to 3 minutes.
04 -
Transfer a portion of the roux to a small bowl, whisk in the egg yolk quickly until combined, then whisk this mixture back into the saucepan.
05 -
Reduce heat to low, add American cheese pieces, half of the shredded cheddar, and Italian cheese blend. Stir until cheese melts completely and sauce is smooth.
06 -
In a 9x13" baking dish, stir cooked pasta with cheese sauce until evenly coated and spread in an even layer.
07 -
Sprinkle remaining shredded cheddar cheese over top and broil, watching closely, until cheese is melted and golden brown.
08 -
Remove from oven carefully, allow to rest for 10 minutes before serving warm.