sheet frozen puff pastry, thawed but still cold (follow package directions)
ounces semisweet chocolate, cut in small dice
cup heavy cream
large egg yolks (if using raw eggs is a concern for you, substitute the yolks of 2 pasteurized eggs)
cup heavy cream, whipped to soft peaks
Adjust oven rack to lower-middle position and heat oven to 425 degrees. Unfold pastry on a lightly floured work surface and roll it into a 12-inch square. Fit into a 9-by-1-inch round tart pan, making sure the pastry is not stretched. Trim excess pastry from pan by pressing around the perimeter with the tip of your thumb. Prick pastry all over with a fork. Spray the bottom side of a 9-inch Pyrex-type pie plate with vegetable cooking spray, then place it in the tart pan to keep the pastry from puffing excessively. Bake until crisp and golden brown, 20 to 22 minutes. Remove pie plate and let tart shell cool to room temperature. Meanwhile, microwave cream and chocolate in a 1-quart Pyrex-type measuring cup on high power until cream is hot enough to melt chocolate, about 3 minutes. (Or heat cream and chocolate together in a double boiler.) Whisk until smooth. In a small bowl, whisk egg yolks. Slowly whisk a cup or so of the chocolate mixture into the yolks (this keeps them from curdling). Whisk this chocolate-egg mixture back into the remaining chocolate and stir until completely blended. Pour chocolate filling into tart shell. Cool until filling has set. (Can be covered loosely and refrigerated overnight. Bring to room temperature before serving.) Serve with whipped cream and optional raspberries.