Arrange 2 oven racks in the top and bottom thirds of the oven and preheat to 350 degrees F. Line 2 baking sheets with parchment paper. Whisk together the flour, ginger, baking soda, cardamom, salt and 2 teaspoons black pepper in a medium bowl; set aside. Beat the brown sugar and butter together with an electric mixer at medium-high speed until pale and fluffy, about 2 minutes. Scrape down the sides, add the egg and beat to combine. Add the molasses and beat to combine. Slowly add the flour mixture and beat until just combined.
Shape the dough into walnut-sized balls, about 1 tablespoon each, then roll them in sanding sugar. Place the cookies 2 inches apart on the prepared baking sheets and flatten slightly.
Bake, rotating halfway through, until puffy and crackled on top, about 10 minutes. Cool on baking sheets for 5 minutes, then remove to a wire rack to cool completely.
Meanwhile fold the cayenne, 1/2 cup crystalized ginger, and 4 teaspoons black pepper into the ice cream. Allow to re-freeze for 10 minutes. Once the ice cream is hard enough to scoop, sandwich about 1/4 cup ice cream between pairs of cookies. Re-freeze for at least 2 hours.
Combine the remaining 1/4 cup crystallized ginger with the remaining 4 teaspoons pepper in a medium bowl. Roll the ice cream sandwich sides in the mixture. Serve immediately or individually wrap in plastic and keep in the freezer for up to 1 week.
When measuring flour, we spoon it into a dry measuring cup and level off the excess. (Scooping directly from the bag compacts the flour, resulting in dry baked goods.)
Copyright 2017 Television Food Network, G.P. All rights reserved.