Preheat oven to 350 degrees F.
Combine all ingredients (except frosting and pecans) in a large mixing bowl, mix with an electric mixer on low speed for 2 minutes. Pour mixture into a buttered 13x9* baking dish and spread evenly into pan.
Bake 25 minutes or until toothpick inserted into center comes out clean. Cool completely, about 1 hour (I'd recommend covering with saran wrap after cooling 20 minutes to help retain moisture).
Frost with Cinnamon Cream Cheese Frosting and sprinkle optional chopped nuts evenly over top. Cut into bars.
*A few people have commented below mentioning that these bars seem a bit thin. If you want a thicker, more cake like bar then either make 1.5 the recipe in a 13x9 pan, or do just 1 of the recipe in a 9x9 pan and bake a bit longer. I personally like the thinness (it makes them more bar-like) so I make them just as listed, but make them according to what you prefer.