Step 1: Preheat your oven to 400°F (200°C). Line a large baking sheet with parchment paper.
Step 2: In a large bowl, toss the sliced crookneck squash with 2 tablespoons of olive oil, ½ teaspoon of salt, and ¼ teaspoon of black pepper until evenly coated.
Step 3: Spread the seasoned crookneck squash in a single layer on the prepared baking sheet. Roast for 15-20 minutes, or until tender-crisp and lightly golden brown. Flip halfway through roasting.
Step 4: While the squash roasts, heat the remaining 1 tablespoon of olive oil in a large skillet or Dutch oven over medium heat. Add the chopped onion and sauté for 3-5 minutes, until softened and translucent.
Step 5: Add the minced garlic and cook for another minute until fragrant. Pour in the vegetable broth and bring to a simmer, scraping up any browned bits from the bottom of the pan.
Step 6: Stir in the heavy cream, fresh thyme, and fresh sage. Reduce the heat to low and let the sauce gently simmer for 5-7 minutes, allowing it to thicken slightly and the flavors to meld. Season with salt and pepper to taste.
Step 7: Carefully transfer the roasted crookneck squash into the skillet with the creamy herb sauce. Gently toss to coat all the squash pieces evenly.
Step 8: Stir in half of the grated Parmesan cheese until melted and fully incorporated into the sauce.
Step 9: Serve immediately, garnished with the remaining Parmesan cheese and a sprinkle of extra fresh herbs.