Combine egg yolks, egg, and 3/4 cup sugar in a medium mixing bowl; beat at medium speed of an electric mixer until well blended.
Combine flour, baking powder, and spices in a small mixing bowl; stir well. Gradually add to egg mixture alternately with molasses; beat well.
Cook chocolate and butter in top of a double boiler over simmering water, stirring constantly, until mixture melts. Add to batter, mixing well. Stir in bourbon and pecans.
Spoon batter into a well greased 13- x 9- x 2-inch baking pan. Bake at 325° for 30 minutes or until a wooden pick inserted in center comes out clean. Cool in pan on a wire rack. Sift powdered sugar over cake, and cut into 3- x 1-inch bars.