How to Make It
Cook the pasta in a large pot of boiling, salted water until it is al dente, according to package instructions. Drain and rinse under cold water until it is completely cooled. Set aside.
Melt the butter in a large pot over medium heat. Whisk in the milk, eggs, cheese, salt, ground mustard, paprika and black pepper. Continue to stir until the cheese is completely melted, and then cook for another 2 to 3 minutes until the sauce thickens slightly.
Add the pasta and spinach to the cheese sauce and cook for another minute or until the pasta is heated through. Serve warm.