Put some olive oil in a pan and fry the onion and garlic cubes until translucent. Add the chicken thighs and fry until golden brown on all sides. Crush the Szechuan pepper with salt in a mortar and season the legs with it. Deglaze with half of the beer and cover and simmer for approx. 40 minutes. Pour in the rest of the beer and let it boil briefly. Cut the parsley into fine strips and pour over them.