In a small bowl, mix sugar and cinnamon. Set aside
Cream together butter, sugar, and eggs. Add buttermilk, flour, and baking soda. Divide ½ of the batter into two greased loaf pans (1/4 in each pan).
Sprinkle cinnamon sugar mixture on top of the batter in each pan, reserving about ¼ to sprinkle on the top.
Evenly add remaining batter to your two pans; sprinkle the rest of your cinnamon topping.
Bake at 350 degrees for 45-50 minutes or until baked through.
Cool for 20 minutes before removing from pan.