Prepare the corn by cutting kernels off the cob or measuring out frozen/canned corn.
Heat olive oil in a large pot over medium heat, sauté diced onion for 5 minutes until translucent, then add minced garlic and cook for 1 minute.
Add corn kernels, vegetable broth, chili powder, cumin, salt, and pepper to the pot. Bring to a boil, then reduce heat and simmer for 15 minutes. Blend the soup until smooth.
Stir in heavy cream and heat through for another 5 minutes. Adjust seasoning, then add cotija cheese, cilantro, and lime juice. Serve hot, garnished with avocado and extra cotija cheese.