The squash can be either microwaved or baked. If you are baking it, preheat the oven to 375 degrees F.
With a sharp knife, cut the squash in half lengthwise (be careful not to cut yourself, the shell can be difficult). Scrape out the seeds from both cavities with a spoon.
If you are using the microwave, place both halves cut side down on a plate and microwave in 4 minute increments until a fork slides into the squash easily without pressure. If you are baking the squash, place the squash halves cut side down on a baking sheet and bake for about 45 minutes (or until fork tender).
Let squash cool. Using a fork or spoon, scrape the strands of squash out into a bowl.
In a large skillet, heat the oil over medium heat. Add garlic and saute briefly (about 1 minute). Add spaghetti squash and saute 2-3 minutes, stirring so as not to burn.
Add chicken broth, salt and pepper, and sundried tomatoes and simmer until heated through. If it is too thick for your taste, add some more chicken broth. Taste and add more salt if desired.
Sprinkle grated parmesan on the squash while it is still on the burner and gently simmer until it melts in (2-3 minutes). Cover the skillet to speed the melting process if desired.
Garnish with thyme or savory herbs.