In a large pot, heat the olive oil over medium heat. Add the diced onion and sauté until translucent, about 5 minutes.
Stir in the minced garlic and cook for an additional 1 minute until fragrant.
Add the corn kernels, vegetable broth, chili powder, cumin, smoked paprika, salt, and pepper. Bring to a boil, then reduce the heat and simmer for 15 minutes.
Using an immersion blender, blend the soup until smooth. (Alternatively, you can carefully transfer the soup to a blender in batches and blend until smooth.)
Stir in the heavy cream and simmer for another 5 minutes to heat through.
Remove from heat and stir in the lime juice and half of the cotija cheese.
Serve hot, garnished with the remaining cotija cheese, chopped cilantro, and diced avocado.