Prepare the acorn squash by peeling, removing seeds, and cutting into evenly sized cubes to ensure uniform cooking.
Add squash, onion, garlic, and broth to the crockpot, ensuring the ingredients are evenly distributed for balanced flavor.
Cook on low for 4–6 hours or high for 2–3 hours until the squash becomes soft and tender when pierced.
Blend the cooked mixture until completely smooth using an immersion blender or standard blender in batches.
Stir in cream, butter, and seasonings, allowing the soup to cook for an additional 10–15 minutes to fully develop flavor.
Adjust consistency with extra broth if needed, then serve warm with desired garnishes.