Two sheets of different colored doughs may be rolled together, as shown below. When sliced, these become pinwheel cookies. Prepare Vanilla Icebox Cookies, omitting the lemon zest. Divide the dough in half. Knead or gently mix into half the dough 2 ounces (55g) semisweet or bittersweet chocolate, melted. If the dough is soft, chill until firm. Roll the vanilla and chocolate doughs separately into equal-sized ⅛-inch-thick rectangles. Layer the chocolate dough over the vanilla dough and roll up like a jelly-roll. Chill, slice, and bake as directed above.