In a Dutch oven cook pasta according to package directions, adding broccoli during the last 5 minutes of cooking. Reserve 3/4 cup of the pasta cooking water. Drain pasta and broccoli; return to pan.
Meanwhile, in a large bowl combine beans, garlic, and 3 tablespoons of the oil. Mash about 1/2 of the bean mixture. Stir in basil, pasta water, and salt. Stir into pasta and broccoli in Dutch oven. Cover and keep warm.
For croutons, in a large skillet heat remaining oil over medium heat. Add bread cubes and crushed red pepper. Cook and stir 1 to 2 minutes until crisp. Top pasta with croutons and, if desired, basil.