Clean, wash and cut the leek into 4 pieces. Cook in boiling salted water for 5 minutes, drain well. Wash the chicory and cut out the stalk in a wedge shape. Sprinkle with lemon juice.
Wrap each with a slice of bacon and cheese. Place in an ovenproof dish. Wash, quarter and seed the tomatoes. Finely dice the fruit flesh. Wash and chop the oregano. Sprinkle both on the wrapped vegetables.
Bake in a preheated oven (electric cooker: 200 °C/ gas: level 3) 12-15 topping.