Coat a piece of aluminium foil thinly with oil. Caramelise oat flakes and 3 tbsp. maple syrup in a coated pan. Finally, add butter, stir in briefly and spread the oatmeal crunch on the aluminium foil. Let it cool down.
Cut grapefruits in half crosswise. If desired, remove the individual segments from the separating skins and the shell with a sharp knife.
Line a baking tray with aluminium foil, place grapefruit halves on top and sprinkle each half with 1 tbsp. brown sugar and sprinkle with 1 tsp. maple syrup. Gratinate under the preheated grill for about 10 minutes.
Serve the finished grapefruit halves with 1 tablespoon cream yoghurt and oatmeal crunch. Sprinkle each with 1 teaspoon maple syrup.