For the chocolate gingerbread mousse, beat the egg yolks, eggs and sugar with a mixer until creamy. Chop the chocolate and let it melt carefully on a water bath.
Chop the gingerbread in a stand mixer and mix with the gingerbread spice. Whip the cream until stiff. Quickly stir the liquid chocolate into the egg mixture, then gradually stir in the gingerbread crumbs and whipped cream. Pour into a large enough bowl and refrigerate for one night.
For the rum cherries, drain the cherries through a sieve, reserving the juice. Caramelize sugar and butter in a saucepan over medium heat. Extinguish with cherry juice and simmer gently. Season with cinnamon and rum, then add cherries and let bubble up again. Add the cornstarch mixed in water, let it boil again and thicken the sauce with it. Allow the cherries to cool and serve with the chocolate and gingerbread mousse.