4 cups (400 g) small cauliflower florets (about 1/2 cauliflower)
1 stalk celery, thinly sliced
1/4 cup (55 g) butter
2 skinless, boneless chicken breast halves, diced
2 tbsp unbleached all-purpose flour
1/2 tsp dry mustard
1/4 tsp onion powder
1/4 tsp garlic powder
1/4 tsp sweet paprika
1/4 tsp celery salt
2 cups (500 ml) milk
3 cups (300 g) grated sharp orange cheddar cheese
1/4 cup (20 g) grated Parmigiano-Reggiano cheese
Salt and pepper
In a large pot of salted boiling water, cook the pasta al dente. Drain and oil lightly. Set aside.
Meanwhile, in a large oven-safe skillet over high heat, cook the cauliflower and celery for 5 minutes in half of the butter (2 tbsp). Add the chicken and the remaining butter (2 tbsp). Continue cooking until the chicken is lightly browned. Season with salt and pepper. Add the flour and spices. Cook for 1 minute, stirring constantly. Add the milk and bring to a boil, stirring and scraping the sides and bottom of the skillet.
With the rack in the middle position, preheat the oven’s broiler.
Remove the skillet from the heat and add half of the cheddar cheese (1 1/2 cups/150 g) and the Parmesan. Combine until the cheese has melted. Stir in the pasta and coat with the sauce. Adjust the seasoning. Sprinkle with the remaining cheese (1 1/2 cups/150 g).