I just made this up last night... and it came out pretty good!!

You need:
2 large bunches up cauliflower, washed, cut into small pieces (No stems) and bioled until soft in salted water
1 cup shredded cheddar
2 cups sour cream
2 tbsp butter
2 small bunches of green onion chopped finely
salt and pepper to taste (I used none, and it had enough flavor)

Mix cooked cauliflower with butter, green onion, sour cream, and 1/2 of the cheese. Place mixture in baking dish and bake at 375 for about 15-20 minutes (until bubbling) Remove from oven and stir, cover with remaining cheese and bake until cheese bubbles.

Sorry, but I do not know the carb count for this.