Wash and clean the rhubarb and strawberries. Halve or quarter strawberries depending on size. Cut the rhubarb into pieces about 2 cm long. Bring 180 ml apple juice, lemon juice and 2 tablespoons sugar to the boil.
Add rhubarb, bring to the boil and simmer for about 2 minutes. Stir 2 tablespoons of apple juice and pudding powder until smooth, thicken juice with it. Fold in strawberries. Cut the biscuits into thirds and put them into an ovenproof dish (approx. 1 litre capacity).
Mix 5 tablespoons of apple juice and vodka and sprinkle on cookies. Spread the groats on the cookies. Beat the egg whites with the whisks of the hand mixer until stiff, adding 100 g sugar.
Spread the meringue loosely in the mould. Bake in the preheated oven (electric range: 200 °C/ convection oven: 175 °C/ gas: level 3) for 5-10 minutes until golden brown.