How to Make It
In a large bowl, toss the berries with the sugar and let macerate at room temperature for at least 1 or up to 4 hours; stir gently from time to time.
In a medium bowl, beat the mascarpone with the candied ginger, sugar and vanilla until well blended. Slowly beat in the heavy cream just until the mixture forms soft peaks. Refrigerate for up to 3 hours; whip briefly before serving.
Preheat the oven to 425° and lightly butter 2 baking sheets. In a large bowl, sift the flour with 1 cup of the sugar, the ginger, baking powder, cinnamon, baking soda, allspice, salt and pepper; whisk to combine. Using a pastry cutter or 2 knives, cut in the Molasses Butter until the mixture resembles small peas.
In a large measuring cup, whisk the buttermilk with the egg yolks. Stir 1 cup of the liquid into the dry ingredients. Using your hands, squeeze the dough until smooth; if necessary, stir in a little more liquid, but don't let the dough become sticky. Reserve the remaining liquid for glazing.
Turn the dough onto a lightly floured surface and roll out to a 1/2-inch thickness. Using a lightly floured 3-inch star-shaped or round biscuit cutter, cut out as many shortcakes as you can. Pat the scraps together and continue cutting to make a total of 16 shortcakes. Arrange the shortcakes on the prepared baking sheets so they don't touch each other, then brush the tops lightly with the remaining 1 1/2 tablespoons of sugar.
Bake the shortcakes, 1 tray at a time, for about 15 minutes, or until the bottoms are lightly browned. Let cool on a wire rack for 5 minutes. Split the shortcakes with a serrated knife. Set each base on a serving plate and spread with a thin layer of the soft Molasses Butter. Mound a serving of berries on each, add a big dollop of mascarpone cream and cover with the shortcake tops.