Using a sharp chef’s knife, carefully cut the acorn squash in half. Cut a flat spot on the bottom so the acorn squash does not roll around while roasting. Using a spoon, scoop out the seeds and stringy pulp, discard. Careful not to scoop too far through the bottom or it will cause a hole and the stuffing will later fall out.
Brush olive oil evenly onto the squash. Sprinkle a pinch of kosher salt and black pepper onto each squash to season.
Roast for 30 minutes until you can just pierce with a fork (it will be going back into the oven with the stuffing to finish cooking through). [see note]
While the acorn squash is roasting, in a dutch oven over medium/high heat, add in the 3 tbsp of olive oil and the Italian sausage. Fully cook the sausage through, about 8 minutes. Using a slotted spoon, remove the sausage and leave the oils/small bits in the pan. Set the sausage aside.
Lower the heat to medium, add in the diced onion and celery, sauté for 4 minutes until they begin to soften. Add in the apples, sage, thyme, garlic, a pinch of kosher salt, fresh ground black pepper, and crushed red pepper flakes. Sauté for 4 minutes. Return the sausage back into the dutch oven with the vegetables and stir to combine. Allow flavors to meld for 3 minutes.
Using a spoon, evenly add the stuffing into the acorn squashes.
In a small bowl, mix together the panko bread crumbs and parmesan cheese. Sprinkle over the top of each acorn squash.
Place the stuffed squashes into the oven for 15 minutes. The breadcrumbs/parmesan should be toasted brown. Remove from the oven and serve.
Size of acorn squash will affect the roasting time, larger squash may need an extra 10 minutes. Squash should be fork tender.
Acorn squash is best enjoyed freshly roasted. For leftovers, reheat in the oven at 375 for 15-20 minutes.
When eating, I do not eat the skin because it can be tough and bitter.