3 cups all-purpose flour
3/4 cup firmly packed dark brown sugar
4 teaspoons ground ginger
1 tablespoon ground cinnamon
3/4 teaspoon baking soda
1/2 teaspoon ground cloves
1/2 teaspoon salt
1/4 tsp finely ground black pepper
12 tablespoons (1 1/2 sticks) unsalted butter, cut into 12 pieces
3/4 cup molasses
2 tablespoons milk

white chocolate ganache filling (recipe below)
powdered sugar for dusting

Combine the flour, sugar, cinnamon, ginger, cloves, pepper, salt, and baking soda in the bowl of a food processor fitted with the steel blade attachment. Pulse until well combined, about 10 seconds. Scatter butter pieces over flour mixture and pulse repeatedly until mixture is sandy and resembles fine meal, about 30 seconds. With food processor running, add molasses and milk and process until dough is evenly moistened and forms soft mass, about 10 seconds.
If you want to double the recipe, you’ll need to make it in multiple batches.
Divide dough in half and roll into ¼ inch thickness between two large sheets of parchment paper. Place in refrigerator at least two hours (or overnight) or place on a flat surface in the freezer for 20 to 30 minutes, until firm. The colder the dough is the easier it is to work with, so I recommend freezing.
Preheat the oven to 350F and adjust the oven racks to the upper- and lower-middle positions. Line two cookie sheets with parchment paper. Once cold and firm, peel the top sheet of parchment from the dough, flip the dough over onto the parchment, and peel off the other piece. You can cut into any shape you like, but if you want to make linzer cookies make sure you have one cutter that is 1/2 the size of the other (or smaller) to make your “window” in the top cookie. Cut out half the cookies in a solid “base” shape, and cut the remaining half of the cookies so that the smaller cutter forms a “window” hole in the center of the top cookie.
Place on prepared baking sheets spacing cookies 1 inch apart. Bake until centers are just set and dough barely retains imprint when touched very gently with fingertip, anywhere from 8 to 11 minutes depending on the size of your cookies. To bake evenly, rotate the baking sheets halfway through. Cool the cookies on the baking sheets about 5 to 10 minutes or until cool and firm enough to remove from the parchment without breaking. Transfer to a wire rack and cool to room temperature. Gather scraps into a ball and repeat rolling, cooling, cutting, and baking with remaining dough until all is used.

Orange White Chocolate Ganache Filling:

7 oz good quality white chocolate (from bars, not chips)
1/4 cup heavy cream
finely grated zest of one large orange
pinch of salt
2 tablespoons unsalted butter

In the the bowl of a double boiler over a very gentle simmer, break up the white chocolate into small pieces and combine with the heavy cream, orange zest, and salt. Stir with a silicone spatula until the chocolate is completely melted with no solid chunks remaining. Take your time, and be sure that the water in the lower pan never goes above a gentle simmer.
Once the chocolate is melted, remove from heat, add the butter and gently stir until completely melted and combined.
Set aside to cool until firm but spreadable. This will take about an hour or two. I’d recommend that you don’t try to refrigerate it because if it gets too cold it’ll be too firm and you’ll need to melt it again to soften it.

With a small offset icing spatula, or a butter knife, spread a small amount (probably about 2 teaspoons) of the ganache filling on to each base cookie. Top each of the filling-covered base cookies with a top cookie and line the filled cookie sandwiches up in a single layer on a clean surface. Dust all the cookies with a light coating of powdered sugar.

If packing for transport or shipping, I’d recommend refrigerating for at least an hour to fully set the ganache.