Lightly-spray an oven-proof bowl, jug or dish with cooking spray. Crack the 2 eggs into it; add the egg white. Microwave on high until yolks and white are set, about 1:40 minutes to 2 minutes depending on your microwave. Then remove and set aside to cool while you push on with the rest of the recipe.
Remove leaves and stalk from cauliflower, chop into quite small florets, and wash. Put in a covered container with a bit of water and microwave *just* until a fork goes in easily; no longer [See cooking notes / tips below.] Drain, and plunge into cold water bath to cool.
Assemble all the other ingredients down to the celery seed in a large bowl. Chop the egg and add; toss. Add the final 4 wet ingredients (the juice, mustard, relish and mayo), stir, then add the well-drained cauliflower (ideally, if you can, spin the cauliflower in a salad spinner just before adding to salad mixture to get rid of any water trapped in the "curd" of the cauliflower.) Fold gently -- a pair of clean hands work best. Put in covered container in fridge and chill for at least 3 hours before serving.
You can make this a day or two ahead safely if you are using commercially bottled mayonnaise (or salad dressing such as fat-free Miracle Whip®) and store the salad covered in the refrigerator.
Optional: serve from a bowl garnished with fresh-chopped parsley and a few sprinkles of paprika.
We used egg white from a carton. You could also use an egg substitute.A 1 kg / 2.2 pound head of cauliflower, after peeling and stalk removed, is 675 g / 6 cups chopped.Cut the cauliflower florets relatively small so they will cook consistently. Give the florets 4 minutes at first in your microwave, then 2 to 3 minute zaps after that until you figure what time works best for your microwave. The right degree of "cookedness" is pretty key to this recipe. If the florets have too much crunch it will be odd; if they are overcooked they'll fall apart on you and develop a cabbagey smell and flavour. Steaming instead of microwaving would work too. (In a pressure cooker, low pressure for 3 minutes on the veg setting if cut into very small pieces; 4 minutes if larger.)Instead of garlic powder, you could use 2 cloves garlic, minced.In place of the low-fat mayonnaise, you can also try fat-free Greek yoghurt, with a tablespoon of horseradish and a bit of lemon juice.