"Chocolate mousse torte" could be many slightly different desserts. Sometimes names aren't used universally. You'd have to describe what you ate for me to be specfic enough to post an actual recipe.
Was is layers of chocolate cake with chocolate mousse in between? Or a moist dense cake that oozes chocolate when cut into it? Or something else?
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"Bakers are born, not made. We are exacting people who delight in submitting ourselves to rules and formulas if it means achieving repeatable perfection", Rose Levy Beranbaum | 
Chocolate Mousse Torte
