Preheat the oven to 170°C on fan-bake. In a large electric mixing bowl, beat together the butter, Chelsea Soft Brown Sugar and eggs for 2-3 minutes until creamy. Sift the flour, baking soda and cocoa. Add the dry ingredients to the egg mixture with the sour cream and beat for 2-3 minutes until smooth and fluffy. Spoon the mixture into a 12-hole muffin pan lined with cupcake cases or directly into self-standing cupcake cases.
Bake in the preheated oven for 15-18 minutes until the cupcakes are puffed and spongy to the touch. Remove from the oven and set aside to cool.
Beat the butter until smooth and pale. Gradually add the Chelsea Berry Flavoured Icing Sugar, half a cup at a time, with enough of the hot water to make a creamy mixture, beating between each addition until fluffy and pink. When the cupcakes have completely cooled, pipe with a generous swirl of buttercream and top with a raspberry lolly.