Wash and dry squash. Cut in half, place face down in ½ inch water in baking dish (I used two 9 x 13 casserole dishes), bake for 25-30 minutes or until fork tender.
While squash in baking saute onions and garlic in olive oil on medium heat until translucent and tender, about 5 minutes.
Add ground chicken and saute until fully cooked, 8-10 minutes. Stir frequently to break up chunks.
Add in tomatoes and saute an additional 1-2 minutes until skin begins to wilt.
Add spinach and saute 1-2 minutes until wilted into mix.
When squash is done baking divide mixture evenly among boats and serve with desired toppings like parmesan cheese, red pepper flakes, etc.
Notes
There's no need to peel - it holds things together. And then you can decide if you want to eat it or not. It's not my favorite part but it is a lot of fiber!