How to Make It
In a bowl, soak the anchos in boiling water until softened, about 20 minutes. Drain and coarsely chop the anchos.
Heat the olive oil in a small skillet. Add the onion and garlic and cook over low heat, stirring, until tender and lightly caramelized, about 4 minutes. Remove from the heat and let cool.
On a cutting board, chop the anchos and the cooked onion mixture together to make a coarse paste. Transfer to a bowl and beat in the butter, lime juice, salt and maple syrup.
Light a grill, preferably charcoal. In a bowl combine the olive oil, molasses, vinegar and chile powder. Brush the steaks on both sides with some of the mixture and season with salt and pepper. When the fire is hot, sear the steaks until well browned on the outside, about 3 minutes per side. Remove the steaks from the grill and spread the coals to cool them down. Return the steaks to the grill and brush with more of the molasses mixture. Grill slowly, turning and rotating, until rare to medium rare, about 8 minutes per side. Transfer to a large platter and let rest for 10 minutes. Thinly slice the steaks and serve with the ancho butter.