Peel grapefruits and oranges so that the white skin is completely removed. Remove the fillets with a sharp knife between the parting skins. Squeeze juice out of the parting skins. Cut the fruit fillets into cubes, except for 1/3 for garnishing. Pluck or cut the brioche into pieces
Mix starch and milk. Beat eggs and sugar until frothy. Bring cream and approx. 50 ml juice to the boil. Pour cream mix and milk to the eggs. Pour half of the brioche onto the bottom of the glasses (each containing approx. 200 ml). Spread 1/2 of the fruit cubes over it and pour half of the cream mixture over it. Add another layer of brioche, the rest of the fruit cubes and cream
Place the jars in a water bath and bake in a preheated oven (electric cooker: 150 °C/ circulating air: 125 °C/ gas: see manufacturer) for approx. 20 minutes. Remove the glasses and let them cool down. Put them in the refrigerator and let them cool down for about 1 hour. Before serving, let stand at room temperature for about 10 minutes and decorate with the remaining fruit fillets
Waiting time approx. 45 minutes