Drizzle in unsalted margarine or oil. Taking care not to deflate the mixture too much. Pour batter into prepared pan. Bake 35-40 minutes until cake is set in center or is firm to the touch. Using the parchment paper as an aid, roll up cake into a jelly roll or log.
Wrap log in a new sheet of parchment paper and wrap in a clean, kitchen towel.
Let cake rest this way 20-30 minutes to allow it to retain log shape. Butter cream should be whipped 2-4 minutes. Re-roll into a log. Wrap snugly in parchment paper and place in freezer while making chocolate glaze. Before glazing, let cake warm close to room temperature.