
Carefully pierce the spaghetti squash into the center with a knife several times. Place on a microwave-safe plate and cook on high for 8-12 minutes or until tender. Let cool while you prepare the chicken.
Season the chicken with salt, pepper and Italian seasoning.
Melt 1 tablespoon of the butter in a large, deep skillet over medium-high heat. Add the chicken and cook until it's no longer pink in the center, about 7 minutes.
Remove the chicken from the pan, place on a plate and tent with aluminum foil to keep warm.
Add the remaining butter to the pan along with the garlic and shallot. Cook 1-2 minutes or until they just start to soften.
Mix in the sun-dried tomatoes and cook an additional minute.
Pour in the heavy cream and cook until hot and bubbly, about 1-2 minutes.
Turn off the heat and stir in the Parmesan cheese and spinach. Add the chicken and any accumulated juices back to the pan.
Once the squash is cool, cut it in half length-wise, remove the seeds and scrap out the strands with a fork.
Stir the squash into the cream sauce until evenly coated.
Garnish with fresh parsley, if desired.