Preheat oven to 400 degrees.
Using a sharp knife cut off each end of the acorn squash removing as little as possible, then cut in half.
Spoon out the seeds.
Brush olive oil on the insides (yellow part) of the acorn squash. Sprinkle with salt and pepper.
Bake, cut side (yellow side) down for 20-30 minutes depending on size of your squash until tender.
While the squash is baking, cook the sausage in a pan.
Remove the cooked sausage, turn heat to medium and add 1 tsp olive oil.
Add onions to the pan and sauté for 2 minutes. Add garlic and spinach to the pan and continue to cook until the onions brown and spinach wilts (about 1-2 minutes).
Take off the heat and stir in thyme, bread crumbs, and parmesan cheese.
Once squash has finished baking and reached desired tenderness spoon in mixture until the squash is filled.
Return to the oven and bake an additional 3-5 minutes.
Remove from oven and top with remaining parmesan cheese.