This was the best carrot salad I've ever made, and I've made a lot of good carrot salad. The difference was the variety of carrot, something that came in our CSA box. They had red skin but were orange underneath. Grating didn't release juice like other varieties, maybe the dressing adhered better.
1 tbsp. Dijon mustard (I prefer Amora but this was Trader Joe's)
1 tbsp. French red wine vinegar (I use Vilux or Beaufor)
3 tbsp. olive oil (I use TJ's Kalamata)
1 tsp. salt
1/4 cup red onion, diced
1 lb. carrots, peeled and grated
Stir everything but the carrots and onions until creamy. Stir in onions and let sit for half an hour or more, stirring occasionally. Toss with carrots and let sit for an hour or so, stirring occasionally.