8 ounces uncooked farfalle (bow-tie pasta)
2 medium yellow squash, halved lengthwise and sliced (about 1 1/2 cups)
1 medium zucchini, halved lengthwise and sliced (about 1 1/2 cups)
2 cups frozen corn kernels
1/2 cup finely chopped fresh basil
1 cup low-fat ricotta cheese
1/2 cup low-fat buttermilk
1/4 cup grated Parmesan cheese
3/4 tsp. salt
1/4 tsp. pepper
1 1/2 cups diced seeded tomatoes
1/2 cup chopped walnuts, toasted

Cook pasta in boiling water 8 minutes.
Add squash and zucchini; return to a boil, and cook 3 minutes. Add corn; cook an additional 2 minutes. Drain well.
Combine basil and next 5 ingredients (basil through pepper) in a large bowl. Add pasta mixture and tomatoes; toss gently to coat.
Sprinkle with walnuts, and serve immediately.

Serves 4.