Ladle a good layer of goose fat into a large roasting tin, then place above the goose while it is having its final 10 mins with the foil on. When you open the oven to remove the foil from the goose, remove the tin for the veg. Carefully lay the vegetables in the hot fat, then use a fish slice to turn them until completely coated. Place the veg above the goose for the final 30 mins, turn them over, then return to the oven while the goose rests for 30 mins. Cook until golden and crisp, turning the oven up slightly at the end if needed.