- Preheat outdoor grill to medium heat. Brush corn and poblano pepper liberally with olive oil. Grill pepper for 6 minutes, turning after 3 minutes. Grill corn for 8-10 minutes turning every 2-3 minutes.
- Set pepper in a bowl and cover with foil. Set corn aside to cool for 5 minutes.
- In the meantime, melt butter in a large pot over medium heat. Add onion and celery, then sauté for 8 minutes to soften. Add garlic and potatoes and sauté for 1 minute longer.
- Slice corn kernels off cob, then peel skin off poblano pepper and chop. Add corn and chopped pepper to pot with sautéed vegetables. Stir in chicken stock, cumin, oregano, and salt. Bring to a boil and reduce heat to medium-low. Simmer for 12-15 minutes, until potatoes are tender, with lid cracked.
- Stir in heavy cream and sriracha. Ladle 1-2 cups of chowder into a blender and blend until smooth. Add back into chowder and cook 2 minutes longer.
- Ladle chowder into bowls and top with cilantro, cotija cheese, chili powder and jalapeño slices.