Onions clean, wash and cut into pieces. Cut end pieces in half lengthwise. Wash, clean and slice the tomatoes. Wash the meat, dab dry and season with salt and pepper. Heat oil in a pan. Fry the meat for about 3 minutes on each side.
Remove and fry the onions in the frying fat for approx. 1 minute, turning them over. Cut baguette into slices. Coat 4 ovenproof dishes with oil. Place the bread, meat, tomatoes and onions in the moulds. Cut the camembert into slices, cut off the rind and spread slices on the meat. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 10 minutes