Horseradish, fennel, and dill happily join forces in this bold purple slaw to offer a punchy, crunchy counterpoint to other picnic fare.

Servings 6 people

1 small red onion thinly sliced
1 1⁄2 tablespoons fresh lemon juice
Kosher salt
1 1⁄2 large fennel bulbs trimmed
4 1⁄2 cups thinly sliced red cabbage
1 large carrot peeled and grated or cut into matchsticks
2 tablespoons finely minced flat-leaf parsley
2 tablespoons finely minced fresh dill
4 1⁄2 tablespoons finely grated fresh horseradish root or 3 tablespoons prepared horseradish
3 tablespoons champagne vinegar
1⁄3 cup good-quality extra-virgin olive oil
3 tablespoons mayonnaise

In a large bowl, toss the onion with the lemon juice and a pinch of salt. Let marinate for at least 10 minutes.
Remove the tough outer layer of the fennel bulbs. Using a mandoline or a sharp knife, thinly slice the bulbs crosswise.
Add the fennel, cabbage, carrot, parsley, and dill to the bowl of marinated onion. Sprinkle with 1 teaspoon salt and lightly massage the mixture with your hands for about a minute to wilt the cabbage a bit. Let the slaw rest for 15 minutes, discarding any liquid that collects in the bowl.
In a small bowl, whisk together the horseradish and vinegar, then whisk in the olive oil. Toss the slaw with the vinaigrette and the mayonnaise and serve.

Gluten-Free Red Cabbage and Fennel Slaw with Horseradish Vinaigrette Recipe