To Cook in Oven: Preheat oven to 375 degrees. Pierce squash a few times with sharp knife (to let steam escape). Place squash on a baking pan lined with foil. Bake spaghetti squash for about 50 minutes, or until a sharp knife pierces easily through skin. Let squash cool for 10 minutes.
To Cook in Crock-pot: Place whole squash in crockpot. Add a little water and cook until tender, about 2-3 hours on HIGH or 5-6 hours on LOW, depending on its size.
Once cooked, cut squash in half, lengthwise. Use a fork to remove and discard seeds. Continue using a fork to scrape squash to get long strands. If the squash seems difficult to scrape, return squash to bake for an additional 10 minutes. Place spaghetti squash strands in a strainer to drain excess moisture. Thoroughly blot dry with paper towels, removing as much moisture as possible.
Heat a large, nonstick pan with butter and garlic, over medium-low heat. Heat for about 1 minute. Add spaghetti squash strands. Toss well. Sprinkle in a little salt and pepper. Continue to toss and cook until thoroughly heated. The spaghetti squash should have a slight crunch.