Follow these simple steps to create your Beef & Mushroom Stuffed Acorn Squash:

1. Preheat the Oven: Preheat your oven to 400°F (200°C).
2. Prepare the Squash: Cut the acorn squash in half and scoop out the seeds. Place the halves cut-side up in a baking dish.
3. Season the Squash: Drizzle the inside of each squash half with olive oil, and sprinkle with salt and pepper. Roast in the preheated oven for about 25-30 minutes, or until tender.
4. Cook the Filling: In a skillet over medium heat, brown the ground beef until fully cooked, about 5-7 minutes. Drain excess fat if necessary.
5. Add Vegetables: Add the chopped onion and minced garlic to the skillet with the beef. Cook until the onion is translucent, about 3-4 minutes.
6. Incorporate Mushrooms: Stir in the diced mushrooms and Italian seasoning. Season with salt and pepper. Cook until the mushrooms are tender, about 5 minutes.
7. Stuff the Squash: Remove the roasted squash from the oven. Spoon the beef and mushroom mixture into each squash half, packing it in gently.
8. Return to Oven: Place the stuffed squash back into the oven and bake for an additional 10-15 minutes to heat through and meld the flavors.
9. Serve: Remove from the oven and let cool slightly before serving.

These steps will guide you in creating this incredible dish with ease!