1.Preheat oven to moderately slow, 170°C (150°C fan-forced). Line 6-hole texas or 12-hole standard muffin pan with paper cases.
2.Sift dry ingredients into small bowl, add butter, egg, buttermilk and syrup; beat mixture with electric mixer on low speed until ingredients are combined. Increase speed to medium, beat until mixture is changed to a paler colour. Stir in chocolate. Divide mixture among cases; smooth surface.
3.Bake large cakes about 40 minutes, small cakes about 30 minutes. Turn cakes onto wire rack to cool.
4.Spread cakes with whipped cream; top with violet crumble.