Position the oven rack about 6 inches from the heat source and preheat the broiler. This ensures that the food will be exposed to intense heat from above, allowing for quick cooking or browning. Placing the rack closer to the heat helps achieve a crispy, golden exterior, which is perfect for roasting vegetables, browning cheese, or crisping the top of a dish.
Line a baking sheet with aluminum foil and arrange the Hatch chile peppers on top. The foil helps with easy cleanup and prevents the peppers from sticking to the sheet. Spreading the peppers evenly ensures they roast uniformly, allowing for optimal flavor and texture during the broiling process.
Broil the peppers under the preheated broiler, turning them once, until the skins are blackened and blistered, about 6 to 8 minutes. Transfer the peppers to a bowl and cover tightly with plastic wrap to steam them, which makes peeling easier. Let them cool for about 20 minutes. Once cooled, peel off the skin, remove the seeds, and dice the flesh. This process enhances the flavor of the peppers, giving them a smoky richness perfect for your dish.
Heat olive oil in a large pot over medium heat. Add the chopped onion and garlic, cooking and stirring until they are softened and fragrant, about 5 minutes. Stir in the diced chile peppers and tomatoes, cooking for another 5 minutes until everything is heated through. Sprinkle the flour into the pot and stir well to combine. The flour helps to thicken the mixture and create a smooth base for the chili.
Pour the broth into the pot and add the cumin, chili powder, and salt. Bring the mixture to a boil, then reduce the heat and let it simmer for at least 30 minutes. This simmering step allows the spices to meld together, deepening the flavor and giving the chili a rich, aromatic base. The longer it simmers, the more the flavors will develop and intensify.