Prep the squash and apples: Peel and cube the butternut squash into 1-inch pieces. Core and chop the apples. Dice the onion and mince the garlic.
Layer in the crockpot: Add squash, apples, onion, and garlic to the slow cooker.
Drizzle with olive oil or dot with butter. Sprinkle in cinnamon, nutmeg, ginger, salt, and pepper.
Pour in the broth: Add enough broth to just cover the vegetables. You can always thin it later if needed.
Cook low and slow: Cover and cook on Low for 6–8 hours or on High for 3–4 hours, until the squash is very tender and easily mashed with a spoon.
Blend until smooth: Stir in the apple cider vinegar.
Use an immersion blender to puree right in the crockpot. For an ultra-silky texture, transfer in batches to a countertop blender. Be careful with hot liquids.
Adjust the texture: If it’s too thick, add more broth.
If it’s thin, let it simmer uncovered on High for 15–20 minutes to reduce.
Finish with richness: Stir in coconut milk or cream, if using. Taste and add salt, pepper, and maple syrup as needed. You want a gentle sweetness with a bright finish.
Serve and garnish: Ladle into bowls and top with pepitas, crispy bacon, chives, or a swirl of yogurt.
Add a pinch of red pepper flakes if you like a little heat.