Fit the pastry to a tart pan or pie tin and pierce the bottom in several dozen places places with the tines of a fork. You can freeze the fitted pastry for fifteen minutes to help keep it from slipping while baking.
Drain the pears and slice them into 1/8 inch slices.
Place the chocolate in a microwave safe bowl and microwave on high for 2 minutes or so. Check as you go to see if the chocolate has melted. Stop the microwave as soon as it is all melted.
Pour and scrape the melted chocolate into the pastry shell. Arrange the pears on top of the chocolate in an attractive overlapping pattern.
Beat the eggs with the sugar and then the cream. Pour this on top of the pears.
Bake for 25 minutes at 400° F (200°C), or until the top begins to brown.
If you wish, sprinkle the tart with two tablespoons of sugar and place it under the grill just until the sugar just starts to caramelize (about two minutes - watch carefully).
Remove from oven and let cool completely before serving.