Mix fat, flour, egg and a little salt to a smooth dough. Cover and chill for about 30 minutes. In the meantime clean, wash and cut the leek into fine rings. Wash and halve the tomatoes. Heat the oil.
Fry the minced meat and leek for about 5 minutes. Season to taste with salt and cayenne pepper. Fold in the tomatoes and let them cool down. Roll out the dough on a floured work surface about 7 mm thick. Cut out circles with tartlet cups. Place the dough circles in greased, tall tartlet cups. Pull the edges up and press them on. Pour in the mincing mixture. Grate the cheese and sprinkle over it. Cook in the preheated oven (electric cooker: 200°C/ gas: level 3) for about 30 minutes.
Place the dough circles in greased, tall tartlet cups. Pull the edges up and press them on. Pour in the mincing mixture. Grate the cheese and sprinkle over it. Cook in the preheated oven (electric cooker: 200°C/ gas: level 3) for about 30 minutes. If necessary, cover with parchment paper for the last 10 minutes. Serve sprinkled with chives