Picnic Classic: Just 4 ingredients.

Prepare the cauliflower: Rinse the cauliflower well and pat dry. Trim away leaves and core, then cut into small, bite-size florets about the size of a classic potato-salad cube. Keeping the pieces on the smaller side helps them soak up the dressing and mimic the feel of potatoes.

Cook the cauliflower: Bring a large pot of salted water to a gentle boil. Add the cauliflower florets and cook for 4 to 6 minutes, just until they are tender when pierced with the tip of a knife but still hold their shape. They should not be mushy.
Drain and cool completely: Drain the cauliflower in a colander and let it sit for a few minutes to steam off excess moisture. Spread the florets out on a clean kitchen towel or a baking sheet to cool completely. This helps keep the salad from getting watery and lets the dressing cling to each piece.

Mix the dressing: In a large bowl (big enough to hold the whole salad), stir together the mayonnaise and yellow mustard until smooth and pale yellow. Taste and add a pinch of salt and black pepper if you like, though the classic version my aunt made relied mainly on the salt from the cooking water.
Add the celery: Stir the finely chopped celery into the mayo-mustard mixture. You want small pieces so you get little bright green flecks and a bit of crunch in every bite.

Combine salad: Add the cooled cauliflower florets to the bowl with the dressing and celery. Gently fold everything together with a spatula until the cauliflower is well coated and the celery is evenly distributed, taking care not to break up the florets too much.
Chill: Transfer the salad to a plastic container with a tight-fitting lid, just like you’d pack it for a picnic. Smooth the top, cover, and refrigerate for at least 2 hours, or overnight if you can. The flavor improves as it chills and the dressing thickens around the cauliflower.

Serve: Give the salad a gentle stir just before serving to redistribute the dressing. Serve well chilled as a side dish, keeping it on ice or returning it to the refrigerator between helpings if you’re outdoors on a warm day.
Variations & Tips