You may substitute other green bean varieties, but since most other types are thicker, increase the cooking time by 2 to 3 minutes (until the beans are tender yet crisp).
- 4 cups (12 ounces) trimmed haricots verts
- 2 Tbsp. balsamic vinegar
- 1 Tbsp. finely chopped shallots
- 1/2 Tbsp. whole grain mustard
- 1/4 cup good-quality extra-virgin olive oil
- 1 1/2 tsp. hazelnut oil
- 1 Tbsp. chopped chives
- 1 Tbsp. plus 1/4 tsp. salt
- 1/4 tsp. freshly ground pepper
- 2 Tbsp. blanched hazelnuts toasted and coarsely chopped
Add haricots verts and cook until tender but still crisp, about 1 minute. Drain immediately and place in ice water until chilled. Drain beans well and set aside.
Meanwhile, add balsamic vinegar to shallots in a medium bowl; let sit 30 minutes. Stir in mustard until combined. Gradually whisk in olive oil and hazelnut oil until blended. Whisk in chives, 1/4 teaspoon salt, and pepper until combined.
Toss in beans and hazelnuts until evenly coated with dressing and serve.