For the Semifreddo: Whip the cream to stiff peaks, set aside.
Combine the yolks, Lambrusco, cola, sugar and mace in a large mixing bowl and whisk to thoroughly incorporate.
Place over a large pot of simmering water and whisk constantly for about ten minutes, until completely turned to foamy peaks and hot to the touch (see note above).
Remove from over water and whisk until cooled to room temperature. Fold sabayon into cream, then scrape into a container and place plastic wrap onto the surface. Freeze overnight or until firm throughout.
Combine all ingredients in a medium saucepan and simmer over medium heat until cherries are soft and syrup is thick and reduced.
Serve: Scoop semifreddo into chilled bowls and top with warm cherries and reduction.