Roughly chop the chocolate and couverture and melt separately in a hot water bath. Whip the cream until stiff. Beat the eggs until frothy. Stir in half the chocolate. Carefully fold in the cream.
Pour into portion bowls and let cool. To decorate, spread the rest of the chocolate and couverture thinly on a board (no wood) and chill. Use a spatula to form fine rolls. Just before serving, decorate desserts with chocolate rolls and mint leaves as desired