Bring a large pot of salted water to a boil (2 Tbsp. salt for 2 quarts of water). Add the green beans to the water and blanch only for about 2 minutes or so, until the beans are just barely cooked through, then quickly transfer to a large bowl of ice water. Drain when thoroughly cooled.
Place the green beans, red onion, and chopped basil in a large bowl. Sprinkle in the olive oil, toss to coat. Sprinkle in the balsamic and Parmesan cheese. Toss to combine. Season to taste with salt and freshly ground black pepper. Chill until ready to serve.
- 1 1/2 lbs. green beans cut to 2-3”
- 1/2 cup finely chopped red onion
- 2 Tbsp. balsamic vinegar
- 4 Tbsp. olive oil
- 3/4 cup chopped fresh basil leaves
- 3/4 cup freshly grated Parmesan cheese
- Freshly ground black pepper