1. In a large bowl, combine sugar and oil. Stir in eggs. Add orange juice and vanilla.

2. Add flour, salt, baking powder, and cinnamon, stirring into a very thick batter. (If batter is too thin, add the extra 1/2 cup flour.) Fold in chocolate chips and walnuts (if using).

3. Line a large jelly roll pan (or two smaller jelly roll pans) with parchment or waxed paper. Spread the batter onto the prepared pan(s), either into one large strip/log or (if using two pans) two smaller strips/logs. The batter shouldn't go to the edge of the pan, but it will be somewhat runny and should look like a thick cake batter that didn't fill the pan. The middle of the "log" will rise during baking.

4. Bake at 350 degrees for about 30-40 minutes, until the top is dry and lightly browned. Remove from the oven and cool for 10 minutes. Reduce oven temperature to 300 degrees.

5. Using a serrated knife, slice the log of mandelbrot into slices about 3/4-inch thick.

6. Lay slices, cut side down, on clean ungreased baking sheets. Bake at 300 degrees for 20-30 minutes longer, turning once during baking, until mandelbrot is dry.

7. Cool finished mandelbrot on wire racks.

Optional: Melt some chocolate chips in a shallow, long dish. Dip the bottoms of the finished mandelbrot in the melted chocolate and place on waxed paper or parchment paper to cool.