Preheat oven to 400 degrees F (204 C) and use a sharp knife to carefully halve acorn squash lengthwise. Do so by inserting the tip of the knife in between two ridges and pressing all the way through, then pushing/rocking the knife to slice through one half. Repeat on the other side.
Scoop out seeds with a spoon or ice cream scoop and discard (or save for making roasted squash seeds). Drizzle acorn squash with oil and maple syrup - rub with hands to distribute. Place squash on a rimmed baking sheet or 9x13 inch baking dish and cover with foil. Bake for 30 minutes covered, then remove foil and bake for 30-40 minutes more, or until squash is fork tender and golden brown on the edges (baking time will vary based on size). Set aside.
In the meantime, start soup. Heat a large pot over medium heat. Once hot, add oil, onion, and garlic. Sauté for 4 minutes or until onion is softened, then add sweet potato, squash and/or carrots (I used butternut squash and carrots).
Season with a pinch of salt and black pepper and stir. Sauté for 4-5 minutes until vegetables appear slightly softened.
Add vegetable broth and herb of choice (I used sage and bay leaf) and bring mixture to a low boil over medium-high heat. If adding lentils, add at this time.
Reduce heat to low and simmer uncovered for 20-30 minutes, or until lentils and vegetables are tender. Then use an immersion blender or transfer to the blender and blend until creamy and smooth. Return to pot if blended in blender.
Taste and adjust seasonings as needed, adding salt and pepper for flavor balance, herbs for earthiness, or a little maple syrup or coconut sugar for sweetness (I didn't find it needed it).
Once acorn squash are baked, divide soup between the squash and garnish with topping(s) of choice - I went for sautéed kale* and red onion, but baked chickpeas, pomegranate, or cornbread (+ cornbread croutons) would work well here.
*If you’d rather, you can just skip the acorn squash and use soup bowls, but it’s a festive and delicious touch! *To sauté kale, simply heat a skillet over medium heat. Once hot, add oil of choice (coconut and sesame work well here) and kale. Sprinkle with a bit of salt and pepper and sauté, stirring frequently, until just soft and slightly wilted. Serve over soup. *Acorn squash method from Pioneer Woman. *Nutrition information is a rough estimate for one, 1 1/2 cup serving of soup in 1/2 an acorn squash bowl without added maple syrup, lentils, or any garnishes.