For the marinade, mix finely chopped garlic, brown sugar, soy sauce, sherry and approx. 50 ml vegetable stock.
Cut the beef into thin strips approx. 5 cm long and place in the bowl with the marinade. Let it steep in the refrigerator for approx. 2 - 3 hours.
Pour some sesame oil into the hot wok and sear the meat, preferably in about three stages, i.e. fry approx. 200 g in the wok, remove the meat and fry the next batch, etc.
Set the roasted meat aside and fry the carrots, celery and onions briefly, they should still have a bit of bite.
Now add the rest of the broth, the rest of the marinade, the Szechuan pepper and the oyster sauce and season with salt.
Put the meat back to the vegetables and color the sauce a little with sugar couleur if necessary, bring to the boil and thicken the sauce with the starch dissolved in cold water until the desired consistency.