Preheat oven to 350 degrees. Prepare muffin tins by either lining with papers or greasing/spraying with non-stick spray. I used large "Texas" style muffin pans. However, you may use regular if you wish.
Combine all ingredients, except granulated sugar, in a large bowl. Beat with electric mixer for 2 min. Batter is very dense. I suggest using a good stand mixer instead of a hand mixer for this.
Fill prepared pans 2/3 full. Sprinkle tops with granulated sugar, if desired. Bake at 350 for 20-25 min, or until toothpick inserted in center comes out clean. Cool in pan 5 minutes, then remove to a rack to cool completely. Makes 12 Texas muffins or 24 regular sized muffins.