1 teaspoon coriander seeds
1 teaspoon cumin seeds
1 teaspoon fennel seeds
¼ cup olive oil
2 Tablespoon white wine vinegar
1 teaspoon Dijon mustard
Kosher salt and freshly ground pepper
Toast coriander, cumin, and fennel seeds in a dry small skillet over a medium eat, tossing, until fragrant, about 3 minutes. Let cool, then chop. Whisk with oil, vinegar, and mustard in a small bowl season with salt and pepper.
Do ahead: vinaigrette can be made 4 days ahead. Cover and chill.