Finely chop the chocolate and place it in a mixing bowl. In a saucepan, bring the milk and cream to a boil. In a separate bowl, whisk the egg yolks with 50 g of sugar until pale and frothy. Slowly pour the hot milk and cream mixture over the egg yolks, whisking constantly. Cook the custard over low heat (or better yet, in a double boiler), stirring continuously with a wooden spoon until it thickens. Pour the hot custard over the chopped chocolate and stir until completely smooth and well combined. Chill the cream in the refrigerator for at least 5 hours. Meanwhile, caramelize the remaining sugar with the butter in a small pan. Peel and core the pears, cut them into small cubes, and gently add them to the caramel, stirring carefully to coat. Divide the caramelized pears among 4 dessert cups. Pipe the chocolate cream over the fruit using a pastry bag. Garnish with chocolate shavings and caramelized wafers, if desired.