1. In a small bowl, sprinkle gelatin over cold water and let bloom for 5 minutes.

2. In a saucepan, heat milk, espresso powder, and half the brown sugar until warm (do not boil).

3. In another bowl, whisk egg yolks with remaining brown sugar until pale and creamy.

4. Gradually pour the warm milk mixture into the yolks while whisking constantly.

5. Return the mixture to the saucepan and cook over low heat, stirring, until slightly thickened and coats the back of a spoon.

6. Remove from heat, add the bloomed gelatin, and stir until dissolved.

7. Stir in spices and vanilla extract; let cool to room temperature.

8. Fold in whipped cream gently until fully combined.

9. Pour mousse into silicone dome molds, leaving a little space at the top.

10. Press a gingerbread cookie onto each mold as the base.

11. Freeze for at least 4 hours or until firm.

12. Unmold the domes, glaze if desired, and let thaw slightly before serving.