Melt butter over medium heat in a large stock pot. Add butternut squash, onion, garlic, and salt. Saute until squash has softened slightly, about 8 minutes. Add pumpkin ale, apple cider, and broth. Simmer another 10-12 minutes or until squash is totally softened. Using an immersion blender, blend soup until smooth. Whisk in white cheddar until melted, then stir in nutmeg.