Adapted from: Martha Stewart Living 

Preheat oven to 350 F. Butter a 10-by-15 inch baking pan, and line the bottom with parchment paper. Butter the parchment, and set pan aside. Combine flour, baking powder, baking soda, ginger, cinnamon, nutmeg, cloves, and salt in a medium bowl; set aside.

In the bowl of an electric mixer fitted with the paddle attachment, cream butter on medium speed until smooth. Add sugar; beat until light and fluffy. Bean in egg, yolk, and molasses.

Add flour mixture; beat on low until just combined. Add 1/2 of the candied ginger and all of the raisins and beat to combine. Spread dough evenly into the prepared pan, and bake until firm to touch, 18-22 minutes, rotating pan halfway through. Remove from oven and cool in pan before icing.

Make the icing: Combine brown sugar, milk, and butter in a medium saucepan. Stir over medium heat until the butter has dissolved. Remove from heat, and whisk in vanilla and confectioner’s sugar. If the icing’s too thick to drizzle, add a bit more milk. If too then, more confectioners sugar. Let cool slightly before using (but remember, you’re drizzling it, so don’t allow to harden).

Drizzle with icing, and then sprinkle remaining ginger on top of bars. Let stand until icing has set, then cut into squares and serve.