1) Put the ancho pods in a bowl and cover with boiling water. Let sit for 30 mins, then remove the stems and seeds and coarsely chop. Reserve the soaking liquid.
2) Heat the oil in a medium saucepan over high heat. Add the onions and cook until soft. Add the garlic and cook for 1 min. Add the tomatoes, peppers and ancho chillis and cook until the tomatoes soften and break down and the liquid thickens, 20 to 30 mins.
3) Let cool for about and carefully transfer the mixture to a food processor and process until smooth. Add the vinegar, honey, salt, pepper, to taste, and coriander and pulse a few times just to combine. Transfer to a covered container and refrigerate until ready to use.