In a large skillet, heat the oil and add everything except the cilantro. Sauté until softened and charred, about 8-10 minutes. Tip: char the onions separately, as they take a little longer than the rest of the vegetables.
Remove the garlic and allow it to cool slightly before squeezing the flesh out of the skin.
Add the remaining ingredients to a blender along with the garlic and cilantro. Season to taste with salt and blend until you reach your desired consistency.