Cut the rhubarb into about 1 cm pieces and mix well with the remaining ingredients. Put everything in an ovenproof dish and cook in an oven preheated to 180 ° C for around 20 minutes until the rhubarb is soft; stir 2 - 3 times.
Then mash a little with a fork as required / taste, allow to cool to room temperature and serve with vanilla ice cream or Greek yoghurt.