Wash the orange, rub dry, peel off the skin of half the orange in zests. Slowly heat milk, butter, orange zests and 50 g sugar in a pot until the butter has melted. Add breadcrumbs, stir in and let cool down for about 10 minutes.
Separate eggs. Stir in egg yolks. Pour the custard mixture into a greased mould (approx. 1.2 litres capacity) and bake in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for 30-45 minutes.
Remove and allow to cool briefly.
Clean and wash the rhubarb and cut it diagonally into pieces about 2.5 cm long. Chop ginger. Put rhubarb and ginger with 25 g sugar in a hot pan and let it caramelize. Pour the rhubarb over the pudding.
Beat the egg whites with the whisks of the hand mixer until stiff, add 200 g sugar and beat until the sugar is dissolved. Spread the meringue loosely on the pudding. Dessert in a preheated oven (electric cooker: 150 °C/ convection oven: 125 °C/ gas: see
manufacturer) bake for another 15-20 minutes. Remove from oven and serve hot or let cool down.