Begin by blooming the gelatin in a small bowl with cold water. Then melt the espresso, brown sugar, cinnamon, cloves, and nutmeg over low heat, stirring until dissolved.

Remove from heat and whisk in the bloomed gelatin until fully dissolved. Stir in the melted white chocolate until smooth, and allow to cool to room temperature.

Combine mascarpone cheese and heavy cream in a mixing bowl. Whip on medium speed until soft peaks form, approximately 3-4 minutes.

Gently fold the cooled espresso mixture into the whipped mascarpone in three additions until fully combined and homogenous.

Prepare silicone molds on a baking sheet. Spoon the mousse mixture into molds, filling three-quarters full. Press cookie bases snugly into the mousse.

Tap the baking sheet to eliminate air pockets. Place in the freezer for at least 6 hours or overnight.

Combine white chocolate and sweetened condensed milk in a bowl. Heat in 30-second intervals until smooth and glossy, cooling to around 90°F.

Remove frozen mousse domes from molds. Pour the warm glaze over each dome, allowing excess glaze to drip off.

Garnish with cocoa powder or edible glitter before serving. Store leftovers in a covered container in the fridge.