Preheat the oven to 400°F. Prepare two large baking sheets with parchment paper. Add cauliflower and butternut squash to the baking sheets, and coat with olive oil, then season generously with salt and pepper. Roast until golden brown and fork tender, about 35-45 minutes, tossing halfway through.
3 pounds butternut squash, halved lengthwise, seeds removed, 2 pounds cauliflower, cut into pieces, 3 tablespoons olive oil, 1 teaspoon kosher salt, ½ teaspoon black pepper
Meanwhile, in a large stock pot or Dutch oven, melt the butter over medium heat. Add in onion, with a pinch of salt and cook until softened and translucent, about 5-7 minutes. Once softened, add in fresh herbs, spices and garlic, and cook until garlic is fragrant, about 30 seconds.
3 tablespoons unsalted butter, 1 cup yellow onion, diced, 2 teaspoons kosher salt, 6 cloves garlic, minced, 2 tablespoons fresh sage, minced, 2 tablespoons fresh thyme leaves, 1 teaspoon smoked paprika, ½ - 1 teaspoon black pepper, ½ teaspoon red pepper flakes, ½ teaspoon ground nutmeg
Add in the roasted cauliflower and squash, then pour in stock and simmer for 10-15 minutes. After 15 minutes, stir in heavy cream to warm through. Adjust seasonings to taste.
4 cups chicken broth, 1 cup heavy whipping cream
Transfer soup mixture to a blender or use an immersion blender to puree the soup. Once smooth, ladle into bowls and garnish with sour cream or heavy cream, salt, pepper, and herbs. *For an extra special flavor, fry a few pieces of sage in some hot oil on the stovetop for garnishes.
Store in an airtight container in the fridge for up to 5 days. Gently simmer on the stovetop or reheat gently in the microwave.