Bring milk, 1 pinch of salt and lemon zest to the boil. Stir in rice and let it swell covered at low heat for about 40 minutes, stirring several times
Clean, wash and cut the rhubarb into pieces. Bring to the boil with lemon juice and 4-5 tablespoons of water, cover and steam for about 5 minutes. Season with 3-4 tbsp. maple syrup and spread in a large greased casserole dish
Pull rice from the stove, remove lemon peel. Separate egg. Mix egg yolk and 1-2 tbsp. rice, stir in 1 tbsp. syrup with the remaining rice. Beat egg white and 1 pinch of salt until stiff, fold in portions
Spread rice pudding on the rhubarb. Sprinkle with the flakes and sprinkle with 1 tablespoon of syrup. Bake in the preheated oven (electric cooker: 225 °C/circulating air: 200 °C/gas: level 4) for 10-12 minutes, decorate