Pre-heat the oven to 170°C and line 2 x muffin tins (1 x 12 hole and 1 x 6 hole) with cupcake cases.
Beat together the sugar and butter until light and fluffy.
Add the eggs one at a time, beating on a low speed until fully combined.
In a measuring jug whisk together the whole milk, sour cream and vanilla extract and set aside for a moment.
Whisk together the flours, baking powder, bicarbonate of soda and salt in a large mixing bowl until completely combined.
Add the flour mix alternately with the milk mixture, adding the flour in three additions and the milk in two (begin and end with the flour), scrape down the sides of the bowls as needed and mix until just combined.
Finally add in the mincemeat, mixing in until evenly distributed throughout the batter.
Divide the batter between the cupcake cases and bake for 18 minutes. Remove the cupcakes immediately onto a wire rack to cool before piping on the buttercream.