Cut Acorn Squash in half and remove seeds. Drizzle cut side with 1 tbsp olive oil and season with salt and pepper. Place cut side down on a foil lined baking sheet and roast for 30-40 minutes or until tender.
Meanwhile in a large pot, heat remaining 2 tbsp of olive oil. Saute garlic and onions for 5 minutes or until fragrant and tender. Stir in salt, sage, and thyme. Add chicken broth, stir together and bring to a boil. Reduce heat, cover and simmer 10 minutes.
Remove skin from squash and coarsely chop. Add squash and pumpkin to soup stir, cover and simmer on low for another 10 minutes. Use immersion blender to blend soup until creamy. Or blend in batches with a blender or food processor. Return to soup to pan. Add freshly ground black pepper to taste.
Stir in 1 cup of heavy cream. *(to make a healthier soup you can add 1 cup broth in place of cream). Stir until evenly combined. Serve with a dollop of sour cream and roasted pumpkin kernels.
*Use more chicken broth to thin the soup to you're liking if it's too thick.