Cream the sugar, butter and molasses together. Put your stamps in the fridge or freezer to chill until needed. Preheat the oven to 190°C (350°F). Line two baking trays with parchment paper.Set aside 15g (1 tbsp) butter that we're going to use for the glaze later. In the bowl of an electric stand mixer fitted with the paddle attachment, on medium speed, cream together the butter, sugar and molasses for 5 minutes until pale and thick. Make sure to scrape down the base and sides of the bowl periodically. Add in the egg yolk and beat until fully combined. Add the yolk. Into the mixture, add the egg yolk and beat until well combined. Again scrape down the bowl.
Sift in dry ingredients. Sift the dry ingredients, flour, cocoa powder, baking soda, ginger, cinnamon, cloves, salt and pepper, into the stand mixer bowl and beat on medium until the dough starts to come together.
Roll out, stamp and cut the cookies. Roll out. Lightly dust your work surface with equal parts cocoa powder and plain flour, turn out the dough and knead it until all the crumbs are incorporated and the dough is smooth. Flatten the dough into a disk and roll out to about 6mm (¼-inch) thickness. If the dough is too soft then refrigerate for 15 minutes or so. Stamp. Dust the chilled cookie cutters with flour, tapping out any excess and stamp the cookie cutters into the dough applying a firm even pressure. Don't push right through to the work surface though. Cut out. Use a cookie round (slightly bigger than the stamp) and cut out the cookie rounds. Place them onto a baking tray and refrigerate for 15 minutes. Whilst chilling, pre-heat the oven to 190°C (375°F). Bake. Divide the cookies between the two prepared baking sheets and bake for 9-10 minutes. You don't want to overbake these cookies, so check on them at 8 minutes. The cookies will be soft when you remove them from the oven but will firm up as they cool.
Make the vanilla bean glaze. While the cookies are baking, melt the remaining butter that we set aside earlier. In a bowl, whisk the powdered icing sugar, melted butter, milk and vanilla bean paste together until it becomes a smooth thin glaze. Add more milk if the glaze is too thick, it should have the consistency of maple syrup.
Glaze the cookies. Once baked, remove the cookies from the oven and leave them to rest for 5 minutes. Then brush on the glaze whilst still warm. The glaze will dry in about 15 to 30 minutes.