Sift flour, ginger, mixed spice, bicarbonate of soda and salt into a large bowl.
In the stand of a mixer beat butter and brown sugar until light and fluffy about 3 minutes. Scrape down the sides of bowl as needed.
Add egg, vanilla extract and treacle or molasses and beat well until well combined. Add flour mixture to wet mixture . Do not over mix.
Cover dough with a plastic wrap and chill in fridge for 1-2 hours or until you can handle it without it sticking to your hands.
Scoop up two tablespoon of chilled dough and roll each into a ball with your hands. Place a caramel in the centre of 1 ball of dough. Top the caramel with the other ball of dough and roll until into a ball until the sides are sealed. Repeat with the rest of the dough and 19 caramel candies. Refrigerate for 2 hours.
Preheat oven to 160°C, Line a baking sheet with parchment paper. Place cookie balls on the prepared sheet , spreading them at least 4 inches apart.
Bake in oven for 10-12 minutes. Remove cookies from oven. The cookies will appear underdone and soft in the middle. Leave to cool on the baking sheet for at least 5 minutes, then continue cooling on wire racks.