Up to 3 days ahead;
1. Tear 14 sheets of waxed paper, each about 9 1/2 inches long. On one sheet, trace bottom of 9 inch round cake pan. Evenly stack all sheets with pattern on top. With kitchen shears, cut out circles.
2. Into large bowl measure sugar, butter, eggs, cinnamon and 2 cups flour. With mixer at low speed, beat ingredients until well mixed, constantly scraping bowl with rubber spatula. Increase speed to medium; beat mixture 3 minutes or until very light and fluffy, occasionally scraping bowl. With spoon, stir in remaining flour to make a soft dough.
3. Preheat oven to 375º. With damp cloth, moisten one large or two small cookie sheets. Place two waxed paper circles onto cookie sheet. With metal spatula, spread a scant 1/3 cup dough in a very thin layer onto each circle. Bake 8 to 12 minutes until lightly browned around the edges.
4. Remove Cookie sheet to wire rack; cool 5 minutes. With pancake turner, carefully remove cookie still on waxed paper to cool completely. (Allow cookie sheet to cool before spreading waxed paper circles with more dough. The more sheets you have the faster you can bake the cookies.) Repeat until all dough is baked. Stack cooled cookies carefully on flat plate; cover with plastic wrap and store in cool, dry place.
4. Early in day or day ahead;
5. Coarsely grate chocolate squares; set aside. In large bowl with mixer at medium speed, beat cream and cocoa until soft peaks form.
6. Carefully peel off paper from one cookie; place on flat cake plate; spread with about 1/2 c whipped mixture. Repeat layering until all cookies are used, ending with whipped mixture on top. Pile grated chocolate on top of cake; refrigerate until serving time or at least 3 hours before serving so cookies soften for easier cutting