Cut the corn: Remove the kernels from the 4 ears of corn by sliding a sharp knife down each cob. You should have about 3 cups corn kernels. Set the kernels aside and place the stripped cobs in a large pot.
Prep the veggies: Peel the onion and garlic and remove the stem and seeds from the jalapeños, but save all these trimmings for the corn stock. Roughly chop the vegetables and set aside.
Make the corn stock: Add the 8 cups water, reserved onion trimmings, garlic skins, jalapeño cores, and 1 teaspoon kosher salt to the pot with the corn cobs. Bring to a boil, then reduce to a simmer and cook for 1 hour. For even more flavor, add celery, bay leaf, black peppercorns, or fresh parsley if desired.
Sauté the vegetables: Heat the 3 tablespoons olive oil in a separate large stockpot over medium-high heat. Add the chopped onions and season with salt and freshly ground black pepper to taste. Cook for a few minutes, then add the 3 chopped garlic cloves, 2 chopped jalapeños, and corn kernels. Cook for about 5 minutes, or until the vegetables are tender.
Toast the chile powder: Add the 1 teaspoon chile powder and cook for 1 to 2 minutes, stirring, until fragrant.
Add the stock: Place a fine-mesh strainer over the vegetables and carefully pour the corn stock through it. Discard the corn cobs and other solids.
Simmer the soup: Bring the mixture to a boil, then reduce to a simmer. Cover and cook for about 30 minutes, or until the vegetables are very soft.
Blend and add the cream: Carefully purée the soup in a blender (please see notes in the blog post about blending hot liquids), working in batches if necessary, until smooth. Return the soup to the pot and stir in the 1 cup heavy cream. Reheat gently and season with additional salt and freshly ground black pepper to taste.
Make the crumble: Combine the 1/3 cup crumbled blue cheese, 2 tablespoons chopped fresh cilantro or Mexican oregano, and 1 thinly sliced serrano chile in a small bowl.
Serve: Ladle the soup into bowls, top each serving with the blue cheese-chile crumble, and serve immediately with lime wedges and tortilla chips.
