Gingerbread swimmers take a dunk in a bubbly mug of spiced gingerbread-flavored hot chocolate and fluffy marshmallows.
Whisk together the flour, ginger, cinnamon, baking soda, allspice, nutmeg, baking powder and salt in a medium bowl until well blended.
Beat together the butter and granulated sugar in a large bowl with an electric mixer starting on low and increasing speed until pale and fluffy, about 3 minutes, scraping the sides of the bowl down as needed. Beat in the molasses until combined, then the egg. (The mixture will look curdled.) Turn to low speed and beat in the flour mixture a little at a time until the mixture comes together, then increase speed and beat until all of the ingredients are well incorporated and you have a sticky dough. Divide the dough in half, flatten into 2 disks and wrap each in plastic wrap. Refrigerate at least two hours and up to overnight.
Position 2 racks in the top and bottom thirds of the oven and preheat to 350ºF. Line 2 baking sheets with parchment paper. Keeping the other disk refrigerated, roll one disk to an 1/8-inch thickness on a well-floured surface, sprinkling flour on and under the dough as needed and sliding a spatula underneath every so often to prevent sticking. If the dough looks crackly or breaks apart, press it back together from the outside edge in. With a 4-inch gingerbread man cookie cutter, cut out gingerbread people as close together on the dough as possible. Pull away the extra dough around each shape and use a small spatula to transfer the people to the prepared cookie sheets about 1 inch apart. Gather together the scraps, leaving behind the excess flour, and knead them a few times to form a smooth dough again. Reroll them in the same way. (If there are any pieces of dough stuck on your surface, scrape them away with a spatula, flour the surface again and then continue to roll the dough.) Check to see if the cutter fits inside the mugs. If the legs are too wide, gently push the legs of the dough cut-outs closer together to make them fit. Freeze the cookies to firm them, about 15 minutes.
Bake the cookies in the center of the oven racks, rotating the sheets from top to bottom and also turning them 180 degrees around halfway through baking, until they are slightly firm to the touch but not brown, about 12 minutes. Repeat the process with the remaining dough.
Cool the cookies 5 minutes on the baking sheets, then transfer to a rack to cool completely before icing. The cookies will continue to firm as they cool.
Combine the confectioners’ sugar and meringue powder in a large bowl. Add 3 tablespoons water and beat with a hand mixer on low speed until the frosting thickens. The icing should be pure white and thick, but not fluffy and bubbly. (If the frosting is overbeaten, it will get aerated, which makes it harder to work with. If this happens, let the frosting sit for a bit to settle, then use a rubber spatula to vigorously beat and smooth out the icing.) Separate the icing into bowls and color as desired.
Put the icing into piping bags or resealable plastic bags and snip the corners to the desired size. Use the icing to decorate the cookies, piping on bathing suits and sunglasses.
Pipe a little white icing on the widest end of each gumdrop to make a drink with foam. Dot some icing on 1 hand of each gingerbread person and press the drink into the dot to make it stick. Let the cookies set at room temperature, at least 1 hour.
Combine the milk, cocoa powder, sugar, molasses, ginger, cinnamon, nutmeg and allspice in a medium saucepan. Cook over medium heat, stirring occasionally, until the sugar, cocoa powder and spices are dissolved and the milk is steaming, about 5 minutes. Do not let the mixture come to a boil. Whisk in the chopped chocolate a little at a time until smooth.
To serve, divide the hot chocolate among 6 to 8 mugs. Insert a gingerbread person with its arms resting on the rim. Add whipped cream and marshmallows as bubbles in the hot tubs.