macaroni and cheese with cauliflower

So I stole this recipe from Breanne's Real Simple last time I was there and y'know what...we liked it! I even took some to the "new moms group" today and I think they liked it too :) It's super easy too!

*side note: I did not make my own bread crumbs (I'm not that ambitious these days! I just used italian bread crumbs I had in my cupboard...made the cooking a lot faster too! Also, I don't have a 3 quart baking dish, I just used a 9x13 and it filled it up pretty good!

12 oz multigrain elbow macaroni (I couldn't find multigrain so I used regular)
1 head cauliflower, roughly chopped
4 slices multigrain bread, torn
1/2 Cup fresh flat-leaf parsley, chopped
3 Tablespoons olive oil
kosher salt and black pepper
1 onion, finely chopped
1 1/2 Cups grated extra-sharp cheddar (6oz)
1 1/2 Cups reduced fat sour cream
1/2 Cup 1% milk
1 Tablespoon dijon mustard

Directions:
1. Heat oven to 400, cook the pasta according to package directions, adding the cauliflower during the last 3 minutes of cooking time; drain
2. Meanwhile, pulse the bread in a food processor until coarse crumbs form. Add the parsley, 2 T of oil and 1/4 tsp of salt and pepper and pulse to combine; set aside.
3. Return the pasta pot to medium heat and add the remaining T of oil. Add the onion, 3/4 tsp salt, 1/2 tsp pepper and cook, stirring occasionally, just until soft, 5-7 minutes. Mix in the pasta, cauliflower, cheese, sour cream, milk, and mustard.
4. Transfer to a shallow 3-quart baking dish, sprinkle with the bread crumbs, and bake until golden brown, 12-15 minutes