Pasta with roasted broccoli and walnuts

This was surprisingly super tasty, and took about 30 minutes. I got the recipe from Real Simple (Feb 2009). I made it a while ago, and it looks like I also added in some grape tomatoes, cut in half. Tonight, we are having it along with a salad that has chicken added in. Gee, we sure are healthy tonight!
12 ounces short pasta (shells, spirals, etc)
1 to 1 1/2 pounds broccoli, cut into small florets
1/2 cup walnuts, roughly chopped.
(If you don't like walnuts, I think almond slivers might work well.)
1/4 cup olive oil
2 cloves garlic, chopped
salt & pepper
2 tablespoons butter
1/4 cup grated Parmesan

Heat oven to 400 degrees. Cook the pasta according to the package directions. Reserve 3/4 cup of the cooking water, drain the pasta, and return it to the pot.

Meanwhile, on a rimmed baking sheeet, toss the broccoli, walnuts, oil, garlic, 1/2 teaspoon salt, and 1/4 teaspoon pepper. Roast, tossing once, until the broccoli is tender, 18 to 20 minutes.

Toss the pasta with the broccoli mixture, butter, and 1/2 cup of the reserved pasta water. (Add more water if the pasta seems dry.) Sprinkle with the Parmesan before serving.