Roast the Cauliflower: Preheat the oven to 400°F. Place the cauliflower florets on a large baking sheet. Drizzle with the olive oil and season with salt and pepper. Toss until evenly coated. Roast for 25 minutes, or until tender and lightly golden. Let cool slightly.
Cook the Potatoes: Meanwhile, place the potatoes in a large pot and cover with cold water. Bring to a boil and add a generous pinch of salt. Cook until fork-tender, about 15 to 20 minutes. Drain and let cool to room temperature. Cut the potatoes in half.
Make the Dressing: In a large bowl, whisk together the olive oil, red onion, lemon juice, red wine vinegar, Dijon mustard, honey, garlic, salt, and pepper until well combined.
Assemble the Salad: Add the roasted cauliflower, potatoes, celery, dill pickles, dill, and parsley to the bowl with the dressing. Toss gently until everything is well coated.
Serve: Taste and season with additional salt and pepper, if needed. Serve. You can also Refrigerate for at least 30 minutes before serving to allow the flavors to meld. The salad is good chilled or at room temperature.
Notes
Roast the cauliflower until lightly browned for the best flavor.
Salt the potato cooking water well.
Toss the potatoes with the dressing while they're still slightly warm so they absorb more flavor.
This salad can be served chilled or at room temperature.
The flavor improves after chilling for 30 minutes.
Fresh dill really makes this salad shine, don't skip it!
Leftovers keep well for up to 4 days in the refrigerator.