Prepare the sauce by mixing the maple sugar with the Xeres vinegar in a small casserole. Bring to a boil and let reduce by half. Add the veal stock and let reduce once more by a third. (If needed, the sauce can be thickened using corn starch diluted in water.)
If necessary, remove the nerves from the milk-fed veal liver before cutting it into 2 cm wide strips. Mix the flour with the Chili powder and coat the milk-fed veal liver strips with it.
Heat the pan on medium-high heat and pour the oil. Brown the milk-fed veal liver strips for a short amount of time and remove them. Set aside and keep warm.
In the same pan, sauté the onions, the carrots and the peppers for 2 to 3 minutes. Add the bean sprouts and the chopped celery leaves. Salt and pepper and continue cooking for 2 to 3 more minutes. Add the sauce.
When ready to serve, arrange the prepared vegetables in a conic shape on the plate. Lay the milk-fed veal liver strips on top and strew with fresh coriander leaves.