This uses a little butter which means it's vegetarian rather than vegan - but you can certainly use more olive oil instead of the butter to make this a vegan dish.
Although this pasta is meat-free, it's pretty hearty, and the roasted cauliflower adds a nice, rich, roasty, deep flavor. You can cook the cauliflower as much as you like - as long you don't burn it. If you roast it a long time, you'll have tender cauliflower with some crisp bits and some chewy parts. Roast it for a very short time, and you'll have toasty edges and cauliflower that's still got some crispness. There's no right or wrong - it's up to you.
When I make a pasta dish, I think it makes sense for all the pieces to be bite-size so a knife isn't needed. Some cauliflower florets are the right size, but the larger ones needed to be cut into smaller pieces.
I like lemon a lot. If you prefer, start with less lemon juice and add more to taste.
Roasted Cauliflower and Citrus Pasta
2 tablespoon olive oil
1/2 teaspoon salt
1/2 pound dry thin spaghetti
2 tablespoons unsalted butter
Pinch of dried crushed red pepper
1/2 teaspoon dried rosemary*
2 tablespoons fresh lemon juice
2 tablespoons capers
6-8 ounces grape tomatoes
1 teaspoon Buddha Hand or lemon zest
Cut the cauliflower into bite-size pieces. Put it on a baking sheet, drizzle with olive oil, and sprinkle with salt. Roast at 350 degrees until the cauliflower is cooked to your liking - 20 to 60 minutes.
Just before the cauliflower is done, cook the pasta in boiling salted water until al dente. Add the butter, red pepper, and rosemary to the pasta over low heat and cook until the butter is melted.
Add the lemon juice and capers, and stir them in. Add the cooked cauliflower and the grape tomatoes and stir to combine, and cook just long enough to warm the tomatoes. Taste for seasoning and add more salt, if desired.
Add the Buddha Hand zest and stir to combine.
This is also pretty darned good the next day, served chilled or at room temperature.
*If you like, chop the dried rosemary into smaller pieces.