Step 1Cream the butter and sugar until light and fluffy. Add the yolk and egg, mixing to incorporate. Add the flour slowly and blend. Form the dough into a flat disk, wrap in plastic and chill 1 hour.
Step 2On a lightly floured board, roll out the dough to 1/4 inch thick. Drape over the rolling pin and fit into a 9-inch tart pan with removable bottom. Press the dough tightly into the corners and edges. Pinch off the top edge to be flush with the pan. Set in the freezer 30 minutes.
Step 3Heat the oven to 400 degrees. Line the shell with foil then fill with pie weights or dried beans. Bake in the lower third of the oven until pale golden, 15 minutes. Remove weights or beans and bake another 5 minutes.
Step 1Heat the oven to 375 degrees.
Step 2Bring the cream to a simmer in a small saucepan over medium-low heat. Remove from the heat and stir in the chocolate, stirring until the mixture is completely melted. Let cool slightly, then stir in the framboise and mix until well blended. Stir in the egg and mix again until well-blended.
Step 3Pour the chocolate mixture into the prebaked tart shell. Bake the tart just until the edges are set and the center is still trembling, 12 to 15 minutes; do not overbake. Transfer to a rack to cool slightly.
Step 4To serve, cut the tart into thin wedges and serve with plain whipped cream.