Make the cookies In a large bowl, whisk the flour, ginger, baking powder, baking soda, salt, cinnamon, nutmeg, and cloves; set aside. In a stand mixer fitted with the paddle attachment, beat the sugar and butter on medium speed until light and fluffy, about 3 minutes. Beat in the molasses, egg, and vanilla until thoroughly combined, about 1 minute. On low speed, gradually add the flour mixture until just combined.
Divide the dough in half, shape into two balls, and wrap each in plastic. Refrigerate for at least 2 and up to 8 hours.
Position a rack in the center of the oven and heat the oven to 375°F. Line 2 cookie sheets with parchment.
Working with one piece of dough at a time, roll it on a lightly floured piece of parchment until it’s about 1/8 inch thick. Put the parchment and dough onto another cookie sheet and refrigerate for 30 minutes. Cut out cookies with a 5-inch snowflake cookie cutter. Remove excess dough from around the cutouts and transfer them with a spatula to the prepared sheets, spacing them about 2 inches apart. You can gather and reroll the scraps up to 2 times.
Bake one sheet at a time until the cookies begin to darken around the edges, 6 to 8 minutes.
Cool on the sheet on a rack for about 15 minutes. Transfer the cookies directly to the rack and cool completely.
Decorate the cookies In a stand mixer fitted with the whisk attachment, mix the confectioners’ sugar, meringue powder, and 1/4 cup cold water on low speed until blended. Increase the speed to medium and beat until the icing holds thick, soft peaks, 3 to 4 minutes. Test the icing’s consistency by piping a small amount through a piping bag fitted with a straight #2 tip. If it’s too thick, add a few drops of water to the mixture in the bowl. If the icing seems too runny, add confectioners’ sugar, a tablespoon at a time, beating on low speed to blend. Don’t over-beat, or the icing will stiffen and lose its gloss. Keep the icing covered with a damp cloth or plastic wrap until ready to use, and use the icing the same day it’s made.
Put about three-quarters of the icing in a clean 1-quart container. Put the remaining icing in a small container and tint with the blue food coloring. (Stir in coloring a bit at a time until the desired shade is reached.)
Put a small amount of the white icing in a piping bag fitted with a straight #2 tip and pipe the outline of the cookie.
Stir water, a few drops at a time, into the remaining white icing until the icing no longer stays peaked when piped but creates a smooth surface. To test, put a small amount in another piping bag with a #2 tip (the icing will drip, so have a cloth ready). Fill in the lines on each cookie, allow the icing to spread, and be careful not to overfill—use a small paintbrush to help spread the icing if necessary. Let the cookies air dry until the icing is set; 2 to 3 hours.
When the white icing is completely dry, put the blue icing in a clean piping bag fitted with a #2 tip and pipe branched lines connecting opposite tips of the snowflakes. Decorate with dragées while the blue icing is wet.