Line a baking sheet with parchment paper. Place the Romanesco florets and sliced garlic on the baking sheet and drizzle the vegetables with the olive oil. Toss well with your hands to coat. Season to taste with salt and pepper.
Roast 20-25 minutes until tender and lightly browned, tossing half way through.
Meanwhile, prepare the pasta according to the package directions. Drain the pasta, reserving about ½ cup of the starchy pasta water. Return the pasta to the pot.
Pour the contents of the baking sheet into the pasta, including any remaining olive oil. Toss well, adding as much of the reserved pasta water as needed. (See Notes.)
Taste and add more salt and pepper, if needed, and enjoy immediately.
Substitutions: If you can't find Romanesco, this dish is equally delicious with cauliflower or broccoli.Expert tip: Add enough of the reserved starchy pasta water so that it emulsifies with the olive oil and helps the vegetables stick to the pasta.Leftovers: Cover and store for up to 3 days in the refrigerator, then reheat in a microwave. Freezing is not recommended.Variations: Add any of the following to the pot when tossing the pasta with the vegetables: