Cook pasta in boiling water 5 minutes until almost tender; add cauliflower in the last 2 minutes. Drain, and set aside.
Meanwhile, heat oil in a medium sized saucepan over medium heat. Add onion and cook until tender, about 10 minutes. Add garlic and stir constantly for 1 minute.
Whisk ½ cup milk and 2 tablespoon flour together and add to saucepan with bay leaf. Whisk in remaining 1 cup milk. Over medium-high heat, bring to a boil while stirring and cook for 1 minute. Reduce heat to low and stir in cheddar, salt, red pepper, paprika, ground pepper, and butter. Cook, stirring until all melted and combined. Stir in half of the red pepper and half of the green pepper.
Turn off heat and stir in pasta and cauliflower. Spread macaroni mixture into a 2-quart square baking dish. Top with bread crumbs and cheese. Sprinkle with remaining red & green peppers.
Bake 20 to 25 minutes or until golden brown and edges are bubbling.
*Make this gluten free by using 1 tablespoon cornstarch in place of 2 tablespoon flour, and use equal amount of gluten free pasta. Skip the bread crumbs and sprinkle with peppers & extra cheese instead.
Recipe from Living Well Kitchen https://blog.memeinge.com/holiday-macaroni-cheese/