Chocolate Bourbons

Cookie

• 4 oz unsalted butter, cut into pieces
• 4 oz light brown sugar
• 1 oz golden syrup
• 6 oz self-rising flour
• 2 oz unsweetened cocoa powder
• 2 oz corn starch
• 1 - 2 oz water
• 1 pinch fine sea salt

Filling

• 2 ½ oz unsalted butter, softened
• 5 ½ oz confectioners sugar
• 1 oz unsweetened cocoa powder
• ½ tsp vanilla extract
• 1 tbsp boiling water