Preheat oven to 400 F. Split the spaghetti squash in half lengthwise and scoop out the seeds. Sometimes it's easier to cut if you microwave the spaghetti squash whole for 2-3 minutes first. Put the halves cut side down on an oiled baking sheet. Roast for 30-40 minutes or until tender. Do not turn off the oven. Let cool thoroughly, then separate the strands using the tines of a fork and scoop out the flesh into a casserole dish.
Meanwhile, saute the sliced onion in a skillet over medium-high heat in your fat of choice. Cook until translucent but not browned. Set aside.
Combine the coconut milk solids, lemon juice, and salt as per this tutorial to make sour cream. Be sure to see the photo tutorial!
Combine the squash with the sour cream, onion, parsley, chives, garlic powder, and pepper. Taste and adjust the seasoning, adding salt if necessary.
Smooth the top, sprinkle with paprika, and dot with the cold oil or ghee. Return the dish to the oven and cook for 20-30 minutes or until the top is golden brown. Let cool and sprinkle with extra chives just before serving.