Roast the almond slivers in a pan without fat. Take out and let cool down. Wash apple quinces, grate dry and cut in half. Remove the seeds with a ball cutter and hollow out the flesh a little. Sprinkle quince halves with lemon juice. Rinse raisins and dab dry. Mix the almonds (except 1 tbsp. for decoration), raisins and cinnamon
Grease an ovenproof casserole dish. Put quinces in it. Add 1/4 tsp. fat to each quince, spread almond mixture on top and add 1/4 tsp. fat. Cook the quinces in the preheated oven (electric range: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 50 minutes
In the meantime, beat the egg whites until stiff, allow the sugar to trickle in and continue beating for about 3 minutes until the sugar has dissolved. 10 minutes before the end of the cooking time, spread beaten egg whites on the quinces. Take them out and let them cool down a little. Place in small moulds. Decorate with the remaining almonds and serve dusted with icing sugar