You can absolutely use whole dried ancho chiles instead of ancho chili powder for this homemade adobo sauce. Instead of the powder, use 4 medium to large dried ancho chiles. Remove their stems and seeds then transfer to a dry skillet. Toast the chiles over medium heat until slightly softened, pliable and very aromatic. Transfer the toasted chiles to a cutting board and let rest until they’re cool enough to handle. Tear chiles into 1-inch pieces and transfer to the blender with spices, vinegar, hot water and garlic. Blend the sauce as directed in the recipe.