Preheat the oven to 180 degrees C. Line two baking trays with baking parchment.
Put the butter and sugar into a large bowl and whisk until light and fluffy. Crack in the egg and mix until combined.
Add the mincemeat - stir.
Tip in the flour, bicarbonate of soda, ground ginger and white chocolate. Stir until well combined.
Use a tablespoon to spoon 10 balls of the mixture onto the baking trays. Make sure there is plenty of space between the balls for when they spread in the oven.
Bake for 10-12 minutes until crisp at the edges but still soft in the middle. Remove from the oven and allow to cool before eating.