Peel the potatoes, cut into circles, without cutting to the edge, with the help of skewers placed under it;
Cut the tomato into semicircular slices;
Put tomato slices in the potatoes, alternating;
Put the potatoes in a baking dish, add broccoli and cauliflower inflorescences, filling the empty spaces of the mold;
Set aside one slice of grapefruit, squeeze the juice from the remaining one, mix the juice with soy sauce and oils;
Pour the mixture into a vegetable pan, add grapefruit slices, sprinkle with pepper;