Pre heat the oven to 175C
For the compote: combine all ingredients together in a pan and start to cook on a low heat until the water comes out the fruit. Turn up the heat slightly and cook until everything is stewed but still retains a little texture, taste and add more sugar if needed, it depends on how tart the rhubarb is.
For the crumble topping: Place all ingredients together in a food processor and blend together until the mixture resembles breadcrumbs. Lay onto a baking tray in a thin layer and bake in the oven for approximately 20 minutes until golden stir every 5 minutes while baking.
Place the cooked compote into an open proof dish and cover with the topping.
Bake in the oven until the topping is crisp and the compote is hot and starting to bubble up around the edges.
Serve with vanilla ice cream or custard.