Preheat the oven to 190 °C.
Mix all the ingredients for the crumble with your hands, a fork, or in a food processor until you get a kind of bread crumb texture.
Wash the rhubarb and cut it unpeeled into fine strips of half a centimeter.
Place the rhubarb in the baking dish and mix in the honey to taste.
Crush the peppercorns in a mortar, sift them, and sprinkle them over the fruit. Expect the equivalent of a teaspoon of ground pepper.
Sprinkle the crumble over it and shake the dish once so that some of the crumble falls between the fruit. Make sure it is well filled, up to the edge.
Place the dish in a larger pot or on a tray: crumble spills over quickly. This way, you avoid making the whole oven dirty.
Bake for about 30 minutes. Keep an eye on it: the edges burn quickly!
Tips
There is no more than fifteen minutes of work, but after that you have to be patient for 30 minutes before it is allowed out of the oven. And all this time those seductive scents are hanging in your kitchen ... don't peel the rhubarb, the crumble looks so much nicer with that pink -red peel. Cut the slices very finely.