Rhubarb and Anise Crimble Cake

I love this cake, a version of a classic American coffee cake. Ring the changes with peaches or gooseberries, raspberries, cherries or blueberries. I’ve used the young, pink rhubarb stalks that are harvested by candlelight in Yorkshire and available in early spring. Serve with vanilla-flavoured crème fraîche or mascarpone (mix in the seeds of a vanilla pod or 1 tsp vanilla extract).