Preheat the oven to 350°F (175°C). Whisk flour, baking soda, salt, ginger, cinnamon, and cloves in a bowl. In another bowl, cream butter and brown sugar until light. Add molasses and egg yolk, mixing until smooth. Gradually add dry ingredients to form a soft dough. Roll out to 1/4-inch thickness and cut circles slightly larger than the dome molds. Bake for 8–10 minutes until edges are set. Cool completely.

Bloom gelatin in cold water for 5 minutes. Warm the espresso with brown sugar, cinnamon, ginger, and nutmeg until just warm. Stir in gelatin until dissolved. Remove from heat and mix in white chocolate and vanilla. Cool to room temperature. Whip the cream and mascarpone to soft peaks, then gently fold in the coffee mixture until smooth.

Fill silicone dome molds about three-quarters full with mousse. Press a gingerbread cookie round on top, flat side up. Freeze for at least 6 hours or overnight until firm.

Make the Mirror Glaze

Bloom gelatin in cold water. Heat sugar, water, and condensed milk until just boiling. Remove from heat and stir in gelatin. Pour over white chocolate and blend until smooth. Add food coloring if desired. Cool glaze to 90°F (32°C).

Unmold frozen domes and place on a wire rack. Pour glaze evenly over each dome in one smooth motion. Let set, then transfer to a serving plate. Decorate as desired and keep chilled.