cauliflower, pasta and cheese gratin

Last night I was really in the mood for some baked pasta. After minutes of searching I found this yummy recipe:

Ingredients

• 8 cups water
• 6 cups cauliflower florets (about 1 1/2 pounds)
• 3/4 teaspoon salt, divided
• 8 ounces uncooked small seashell pasta
• 1/4 cup all-purpose flour
• 3 cups 1% low-fat milk
• 2 teaspoons chopped fresh or 3/4 teaspoon dried thyme
• 3 garlic cloves, crushed
• 1 cup (4 ounces) shredded reduced-fat sharp cheddar cheese
• 1/2 cup (2 ounces) grated fresh Parmesan cheese
• 3/4 cup finely chopped green onions
• 2 teaspoons Dijon mustard
• 1/4 teaspoon black pepper
• 2 (1-ounce) slices white bread
• 2 teaspoons butter, melted

Preparation

Preheat oven to 400°.

Bring water to a boil in a large saucepan; add cauliflower and 1/2 teaspoon salt to boiling water, and cook 4 minutes or until tender. Remove cauliflower with a slotted spoon, reserving cooking liquid; set cauliflower aside. Bring cooking liquid to a rolling boil. Add pasta, and cook 7 minutes or until al dente; drain and set aside.

Lightly spoon flour into a dry measuring cup, and level with a knife. Combine flour and milk in a saucepan, stirring well with a whisk. Stir in thyme and garlic; cook over medium heat until thick (about 8 minutes), stirring constantly. Remove from heat; stir in 1/4 teaspoon salt, cheeses, onions, mustard, and pepper. Combine cauliflower, pasta, and cheese sauce in a large bowl. Spoon the cauliflower mixture into a 13 x 9-inch baking dish. Place bread in food processor; pulse 10 times or until coarse crumbs form to measure 1 cup. Combine breadcrumbs with butter; sprinkle evenly over cauliflower mixture. Bake at 400° for 20 minutes or until lightly browned.