Mix the herbes de Provence with black pepper and salt. Rub the steaks with this mixture.
Squeeze the juice from half the lemon and pour on the steaks. Leave them to marinate for 15-20 minutes at room temperature.
Cut the cherry tomatoes into circles, and the shallots into rings.
Wrap each steak with foil, put the tomatoes and onions on top, sprinkle with lemon juice. Wrap the edges of the foil tightly.
Heat the oven to 180°C and bake the steaks in foil for 20 minutes.