In a large pot, warm olive oil over medium heat. Add onion. Cook, stirring often, until onions turn soft and golden, 3-4 minutes. Add garlic. Cook 'til fragrant, about 1 minute, stirring frequently.
Stir in butternut squash, salt, maple syrup, nutmeg, pepper and vegetable broth. Transfer to a blender and puree 'til smooth. Or, blend with an immersion blender. Cook on a low simmer for about 10 minutes.
Taste and stir in more salt and pepper, if necessary. Stir in cream just before serving.
Pour it into serving bowls. Top with sour cream and fresh sage, if desired.