Melt butter in a large soup pot or Dutch oven over medium heat. When hot, add the green onions and cook for 1-2 minutes until fragrant and soft.
3 tablespoons butter, ¾ cup sliced green onion
Add chipotle chili powder, milk, broth, and corn. Cook over medium heat about 5-10 minutes just until it begins to boil.
¼ teaspoon chipotle chili powder or mild chili powder for no spiciness, 2 cups whole milk or canned coconut milk, 2 cups vegetable broth, 4 cups frozen corn
Transfer half of soup to a blender or food processor and pulse a few times. Add it back to pot.
Remove a bit of broth and whisk in cornstarch. Add mixture to pot and stir in sour cream, cheese, lime juice, and zest. Cook 3-5 minutes to melt cheese and thicken soup.
⅓ cup sour cream, ⅓ cup cotija or parmesan cheese, 1 tablespoon lime juice, 1 tablespoon cornstarch, 1 teaspoon lime zest
Season with salt and pepper. Serve up the soup topped with more cheese, sliced green onion tops, a sprinkle of Tajin, and a bowl of lime wedges for squeezing.
Salt and pepper to taste, Sliced green onion tops and Tajin for serving