Preheat oven to 180°C/350°F (160°C fan). 

Place oven rack in the middle to upper section of the oven. P

lace cupcake liners in a 12-hole muffin pan. 

Melt White Chocolate Dotties in short bursts of 10 to 15 seconds in the microwave on 50% power or using a double boiler. Stir until smooth and set aside to cool.

In a separate bowl add sifted flour, bicarbonate of soda and baking powder, whisk to combine.

In a separate bowl cream butter and sugar with electric mixer, until light and fluffy. Add the egg and vanilla and beat until combined. Pour in the cooled melted chocolate and beat for approximately 30 seconds, until combined. Add the milk and sour cream and beat for a further 20 seconds until combined. Add dry ingredients and beat on low speed until combined. 

Divide mixture between cupcake liners, filling to about two thirds full. Bake for approximately 20 minutes, or until a skewer inserted into a cupcake comes out clean, with the exception of a few moist crumbs sticking to the skewer. Immediately transfer cupcakes to a wire rack to cool.

Meanwhile, make berry coulis. Place berries, sugar and lemon juice in a saucepan, stir to combine. Bring to a simmer and continue to simmer until the liquid is reduced by half, about 10 to 15 minutes. Pass through a fine sieve to remove the seeds and allow to cool before using.

Meanwhile, make buttercream. Melt White Chocolate Dotties in short bursts of 10 to 15 seconds in the microwave on 50% power or using a double boiler. Stir until smooth and set aside to cool.

Beat softened butter and vanilla with electric mixer until pale. Add half of the icing sugar and beat to combine, then add half of the cream and beat until combined. Repeat with remaining icing sugar, followed by remaining cream. Add cooled melted chocolate and beat until combined and mixture is a smooth, pipeable consistency. When cakes are cool, pipe buttercream in a generous swirl on top. 

To serve the cupcakes, top with fresh berries and a drizzle of coulis.