Cut the lindt truffle balls in half, and place them in the fridge to firm up.

Cream the butter with the brown sugar, and white caster sugar.

Add the vanilla extract, and beat in 1 egg.

In a separate mixing bowl, sift the flour, cocoa powder, baking soda and salt.

Combine the wet and dry ingredients. Add one tablespoon of milk to the dough as it comes together.

Refrigerate the dough for at least 1 hour.

Roll the dough into 1-2 inch balls, and place half a lindt truffle in the center of each.

Place each unbaked cookie on a baking tray at least 2 inches apart from each other, and refrigerate the tray covered for at least 20 minutes.

Preheat your oven to 180 degrees celsius. Take the tray of cookies out of the fridge and let them stand at room temperature for 5-10 minutes before baking.

Bake the cookies for 15 minutes. When the cookies are done, sprinkle them with sea salt. Let the cookies cool on the tray for 5-10 minutes, them remove and place them on a wire rack to cool entirely.