Roasting the Poblano Peppers (Oven Method): For alternative stovetop and grill methods, please refer to the "Notes" section below.

1. Preheat your oven's broiler to high (usually around 500-550°F / 260-290°C) and ensure that your oven rack is placed in the top position of your oven.
2. Place the peppers on a foil-lined baking sheet and transfer to the top rack to broil for 15-20 minutes, flipping them once with tongs.
3. When the peppers have blistered and blackened slightly, and the skin is pulling away from the flesh, remove them from the oven.
4. Using kitchen tongs, transfer the peppers to a heatproof bowl and cover with a tight-fitting lid (or place a plate on top to seal). Allow to steam for 10 minutes—this makes removing the skins easier!
5. Once they are finished steaming, allow the peppers to cool until they can be comfortably handled. Once cooled, peel the skin and discard, then using a knife, carefully scrape the seeds out and discard them along with the stem.
6. Dice the roasted peppers and set them to the side.

Chowder Preparation:

1. In a large soup pot over medium-high heat, add the olive oil (or garlic-infused olive oil). Once the oil is shimmering, add the garlic, green onions, celery, and chopped poblano peppers. Sauté for two minutes, stirring occasionally.
2. Add broth, frozen corn, and diced potatoes. Give it a good stir to combine everything, and then sprinkle in the cumin, cracked black pepper, salt, and chipotle pepper powder. Stir once more to ensure all the flavors meld together.
3. Allow the mixture to come to a boil, then lower the heat to medium and let it simmer until the potatoes are fork-tender.
4. In a large glass measuring cup or a small mixing bowl, combine the 4 oz (½ cup) of the milk and the cornstarch, whisking with a fork or a small whisk to combine until smooth. Ensure that you create this cold cornstarch slurry first before adding it to the soup to prevent clumping.
5. Once the cornstarch is fully dissolved, add the slurry along with the remaining 12 oz (1 ½ cups) milk to the soup pot and stir to combine.
6. Taste for salt and adjust if needed. Once the soup has begun to thicken, it can be removed from heat and served.