Melt chocolate and butter in a large heavy saucepan over medium-low heat, stirring often. Remove from heat, and stir in peanut butter. Let cool slightly. Gradually add chocolate mixture to eggs, beating at medium speed of an electric mixer 10 minutes.
Fold flour into batter. Spoon batter into a greased and floured 9" springform pan.
Bake at 400° for 12 minutes for a gooey dessert, or 15 minutes for a firmer dessert. (Either way, cake will not be firm in center when removed from oven.) Let cool completely. Cover and chill thoroughly.
Remove sides of springform pan. Spoon warm Peanut Butter Cream onto each dessert plate. Top each with a slice of torte. Garnish, if desired.