6 poblano peppers
3 tablespoons olive oil
3 pounds flank steak, cut into 1-inch cubes
1 sweet onion, chopped
32 ounces beef broth
2 tomatoes, chopped
4 garlic cloves, minced
3/4 cup cilantro, minced
1 1/2 teaspoons cumin
1 tablespoon chili powder
1/4 teaspoon mustard powder
1 1/2 teaspoons salt
1/2 teaspoon ground black pepper
3 medium potatoes (like Yukon Gold), peeled, cut into 1-inch cubes
Step 1Using metal tongs, broil poblano peppers over a gas stovetop until the skins blister, about 3 minutes. Broil all sides of the peppers evenly. Immediately place peppers in a large resalable plastic bag and seal bag. Let sit for 15 minutes.
Step 2Peel peppers and remove stems. Throw away the skin, stems, and seeds. Roughly chop peppers.
Step 3Heat oil in a large, heavy pot over medium heat. Cook beef until golden brown on all sides. Remove beef with a slotted spoon; set aside.
Step 4Cook the onion in the same pot until tender, about 6 minutes. Add beef, poblanos, broth, tomatoes, garlic, ¼ cup cilantro, cumin, chili powder, mustard, salt, and pepper. Increase heat to high to bring mixture to a boil. Reduce heat to medium-low, cover and simmer until beef is tender, about 1 hour and 20 minutes.
Step 5Add potatoes and cook for 15 minutes. Skim excess fat from soup. Garnish with remaining chopped cilantro.