Clean, wash and cut the rhubarb into pieces of about 2 cm. Bring to the boil with 150 ml apple juice and 2 tablespoons sugar and steam for about 2 minutes. Stir 2 tbsp. apple juice and starch until smooth. Stir into the boiling rhubarb and simmer for another 2 minutes.
Season with 1-2 tablespoons of sugar if necessary.
Preheat oven (electric cooker: 200°C/circulating air: 175°C/gas: level 3). Break biscuits into pieces and put them into a small casserole dish. Drizzle 5 tablespoons apple juice and Amaretto over them. Wash and clean the strawberries and, depending on size, halve or quarter them.
Fold the strawberries under the rhubarb and spread the compote on the biscuits.
Beat the egg whites with the whisks of the mixer until stiff, adding 100 g sugar. Spread the beaten egg whites loosely over the compote. Bake in a hot oven for 5-10 minutes until the tips turn brown.