Prepare Cookie Base: In a mixing bowl, combine molasses, brown sugar, spices, and egg yolk to form a soft dough. Roll the dough out to about 1/4-inch thick, then cut rounds slightly larger than your silicone molds. Bake at 350°F for 10-12 minutes until firm and slightly golden. Allow them to cool completely.

Make Mousse: Bloom the gelatin by sprinkling it over a few tablespoons of cold water for about 5 minutes. In a saucepan, combine espresso, brown sugar, and spices, stirring until the sugar dissolves. After heating, mix in the bloomed gelatin and melted chocolate until smooth. Let it cool to room temperature.

Whip Cream: In a separate bowl, whip mascarpone cheese and heavy cream until soft peaks form. Gently fold the cooled espresso mixture into the whipped cream without overmixing.

Assemble Domes: Fill silicone molds with the mousse mixture, pressing cookie rounds into the mousse until just submerged. Cover with plastic wrap and freeze overnight.

Glaze: Heat the mirror glaze to 90°F, then pour it over the frozen mousse domes, letting it drip down the sides. Let it set before serving.

Serve: De-mold the domes, garnish with cocoa powder or mini cookies, and keep chilled until serving.