Defrost frozen goose legs overnight in the refrigerator.
Wash the legs, salt and pepper them, rub spices well on the poultry skin.
Preheat the oven to 200 °C (top/bottom heat), place the legs on a baking tray and roast in the oven for about 35 minutes.
Peel the onions, cut them into eighths and add them.
After about 30 minutes, reduce the heat to 170 °C and baste the drumsticks alternately with red wine and hot soup by the tablespoonful (about every 15 minutes, until the end of the roasting time).
Pierce drumsticks several times with baking pin to drain fat. The fat on the tray, together with the soup and red wine, makes a delicious natural juices.
After 1 1/2 hours or when the drumsticks are golden brown, reduce heat to 130 °C until guests arrive. Roast for the last 20 minutes at grill setting (220 °C to 230 °C, preferably convection grill).
Arrange the goose legs and serve.