This is my favorite mock potato salad that can be easily prepared vegan by omitting the egg and mayo.
Preheat oven to 400°. Mix cauliflower with avocado oil, 1 tablespoon mustard, 1 teaspoon salt, ½ tablespoon dill, 1 tablespoon mayo and a few pinches of fresh cracked black pepper until well coated. Spread cauliflower on a large baking sheet lined with parchment paper and bake for 30 to 40 minutes until cauliflower is tender and lightly browned. Allow cauliflower to cool to room temperature or chill overnight.
Mix in remaining ingredients and chill or rest on countertop for 30 minutes before serving. Refrigerate leftovers for up to 4 days. It keeps getting better with age!