Preheat a grill to medium-high or heat a cast-iron skillet over medium-high heat. If using the oven, set the broiler to high and set ears on a foil-lined sheet.

Rub the husked ears lightly with a touch of neutral oil to encourage even charring. Place the corn on the grill or skillet, turning occasionally until you see blistered, dark brown to black spots — about 8–12 minutes total depending on heat.

Let the corn cool until you can handle it safely, then cut the kernels off the cob.

In your pot or Dutch oven, warm 1–2 tablespoons neutral oil over medium heat. Add the diced onion and a pinch of salt, then sauté until translucent and tender — about 5–7 minutes.

Add the minced garlic and cook for an additional 30–45 seconds until fragrant but not browned.

Stir in the charred corn kernels. Pour in the vegetable broth and coconut milk, and add chili powder and cumin. Stir to combine and season lightly with salt and pepper.

Bring the soup to a gentle simmer over medium heat, then reduce to low and let it cook uncovered for 15–20 minutes.

Use an immersion blender directly in the pot to purée the soup to your preferred consistency.

Stir in the juice of 1 lime and taste. Adjust seasoning as needed.

Ladle the soup into bowls and garnish with chopped fresh cilantro and crumbled Cotija if using.