Slice squash in half lengthwise. Scoop out the seeds with a spoon as you would a pumpkin. Then completely submerge both halves in boiling water and cook for about 20 to 25 minutes, or until the inside is tender to a fork and pulls apart in strands. (It is better to undercook if you are not sure). Remove, drain, and cool with cold water or an ice bath to stop the cooking. Then use a fork to scrape the cooked squash out of its skin, and at the same time, fluff and separate the squash into spaghetti-like strands. Discard the skin.
Reheat the squash strands by dipping with a strainer in boiling water just before serving. Top with Primavera Sauce.
Melt 2 tablespoons butter in a medium saucepan over medium high-heat. Add broccoli and saute for about 1 minute. Then whisk in cream and egg yolk and cook for only 1 to 2 minutes. Next, add garlic and cheese and whisk quickly just to heat through. Remove from heat and stir in the rest of the butter and the parsley. Pour over or toss with the hot spaghetti squash. Season with salt and pepper, if desired. Garnish with fresh basil leaves and grape tomatoes.
This recipe is for half of the squash. You may double the recipe to use all of it, or top the other half of the squash with butter, sour cream, cheese, and bacon to make "mock" baked stuffed potatoes.