Preheat oven to 350°. Microwave spaghetti squash (whole) for 3-4 minutes. Cut in half lengthwise; remove the seeds with a spoon. Fill a 9 x 13 pan with about ½" of water; place the squash halves in the pan, cut side down. Bake about 45 minutes. Let the squash cool for about 5-10 minutes.
Using a fork, gently pull the strands of squash away from the peel and place them in a large bowl.
Melt the butter in a large skillet. Add the packet of Garlic & Basil Warm Dip Mix, salt and pepper and squash. Toss gently but thoroughly to coat. Stir in Greek yogurt, if desired. Serve immediately or cover and keep warm until ready to serve. Garnish with Parmesan cheese.