In a large pot, heat olive oil over medium heat. Add chopped onion and cook until translucent.
Add minced garlic, cumin, coriander, and paprika. Sauté for a few minutes until fragrant.
Add diced butternut squash, red lentils, and vegetable broth to the pot. Bring to a boil, then reduce heat and simmer until squash and lentils are tender, about 20-25 minutes.
Use an immersion blender to puree the soup until smooth. If you don't have an immersion blender, carefully transfer the soup in batches to a regular blender and blend until smooth.
Season the soup with salt and pepper to taste. Serve hot and enjoy this Spiced Butternut Squash and Lentil Soup on a chilly day!