How to Make It
Make the beans. Heat the oil in a medium skillet over medium-high heat. When shimmering, add the garlic and onion wedge and cook, stirring constantly until they’re blistered and dark-golden on all sides. This won’t take long. Remove the garlic and onion pieces, or leave them in if you don’t mind pieces of onion or garlic in your beans.
Preheat the oven to 400°F.
Char the poblano pepper over a gas flame, turning until the pepper is mostly blackened. If you don’t have a gas stove, you can broil the pepper or use a nonstick skillet.