Prepare the squash for roasting: Turn your oven to 425°F (218°C) and put your halved acorn squash cut-side up on a baking sheet lined with parchment paper. Drizzle 2 tablespoons olive oil over them, then sprinkle ½ teaspoon salt and ⅛ teaspoon pepper on top.
Roast the squash until tender: Flip those squash halves over so the cut side faces down on your baking sheet. Roast for 30-40 minutes until they're super soft when you poke them with a fork. The skin should look a bit wrinkled when they're ready!
Sauté aromatic vegetables: While your squash is roasting away, heat 1 tablespoon olive oil in your Dutch oven on medium heat. Add 1 chopped onion, 2 chopped carrots, and 3 minced garlic cloves. Cook them for 5 minutes until they smell amazing and start turning brown.
Combine squash with broth: Grab a spoon and scoop out all that roasted squash flesh, then toss the skin in the trash. Add the squash pieces to your pot along with 4 cups chicken broth and 1 tablespoon fresh thyme leaves. Give everything a good stir!
Simmer soup to develop flavors: Turn the heat up to high and let everything come to a boil. Then turn it down to medium-low, put the lid on your pot, and let it simmer for 10 minutes so all those flavors get to know each other.
Blend to creamy perfection: Pour ½ cup half and half into the pot, then grab your immersion blender and blend until it's totally smooth and creamy. Add 1½ teaspoons salt and ¼ teaspoon pepper to taste. Want it sweeter? Blend in 1-2 tablespoons maple syrup until it tastes just right!