1. Preheat oven to 375 degrees F. Coat a 15x10" jellyroll pan with cooking spray and dust with the 2 teaspoons flour. (In lieu of a jellyroll pan, you can use a 13x9-inch cake pan.) Combine 2 cups flour and next four ingredients (flour through salt) in a large bowl; stir well with a whisk.
2. Combine water, margarine, and cocoa in a small saucepan; bring to a boil, stirring frequently. Remove from heat; pour into flour mixture. Beat at a medium speed of a mixer until well-blended.
3. Mix nondairy milk and vinegar or lemon juice, and add "buttermilk," vanilla, and applesauce; beat well. Pour batter into prepared pan. Bake for 17 minutes or until a wooden toothpick inserted in center comes out clean (if using 13x9-inch pan, bake for 22 minutes).
4. For icing, combine margarine, milk, and cocoa in medium saucepan. Bring to a boil, stirring constantly. Remove from heat, and gradually stir in powdered sugar and 2 teaspoons vanilla. Spread over hot cake. Cool completely. Sprinkled with pecans, if desired.
Please note: The cinnamon is NOT optional. It may sound weird, but it is the ingredient that makes this cake what it is--yummy!
**For the applesauce, do NOT substitute mashed banana, because it will ruin the flavor. You can, however, try substituting Ener-G Egg Replacer or some other egg replacer you like. I've just had best results with applesauce when making cakes, plus it is easy and cheap.