This is a great, healthy side dish to bring to a barbecue.

Adapted from epicurious.

1 oz hazelnuts (2 tablespoons)
3/4 lb green beans, trimmed and halved diagonally
2 1/4 teaspoons grainy mustard
1 1/2 teaspoons balsamic vinegar
1/8 teaspoon fine sea salt
4 teaspoons extra-virgin olive oil
1 tablespoon flaxseed oil
1/4 cup finely chopped red onion

Preheat oven to 325°F with rack in middle.

Toast nuts in a small baking pan until centers are golden, 15 to 20 minutes (cut one open to test for doneness). Cool to warm, then rub off any loose skins in a kitchen towel. Coarsely chop nuts.

Cook beans in a 6-quart pot of boiling salted water (1 1/2 tablespoons salt for 4 quarts water) until just tender, 4 to 6 minutes. Transfer to an ice bath to stop cooking. Drain and pat dry.

Whisk together mustard, vinegar, sea salt, and oils. Add nuts and onion and stir well. Pour over beans and toss to coat. Season with salt and pepper if desired.