Turn squash over, skin side up, pierce the skin with a fork a few times.
Turn squash back over, skin side down, brush flesh of squash with olive oil.
Season with garlic salt and pepper.
Place squash, skin side down on a parchment paper lined baking sheet. Bake for 45 minutes.
Move pan up to top rack. Turn oven up to the broil setting. Watch carefully, you just want to broil it long enough to brown the top. About 2-3 minutes.
Remove from broiler and immediately sprinkle with parmesan cheese (if using). Garnish with fresh chopped parsley and serve.
Notes
Spaghetti squash can be a little challenging to cut through. You may find it easier to use a sawing motion with a bread knife instead of a slicing motion with a chef’s knife.
Use a damp paper towel underneath your cutting board to keep the board from moving around while you work.
This dish will keep in the refrigerator for about 2 days. However, we have found that spaghetti squash tastes best if served right away. Day one of leftovers is fine, but by day two the dish will have lost some of its flavor luster.