01 -
Heat oven to 350°F. Grease a 9x5-inch loaf pan.
02 -
Whisk together flour, baking soda, and salt in a bowl.
03 -
Beat butter and sugar until fluffy, about 2 minutes. Add eggs one at a time, then vanilla.
04 -
Alternate adding flour mixture and buttermilk to butter mixture, starting and ending with flour.
05 -
Mix brown sugar and cinnamon in a small bowl.
06 -
Pour half the batter in pan, add half cinnamon mix, top with remaining batter and cinnamon. Swirl with knife.
07 -
Bake 50-60 minutes until done. Cool 10 minutes in pan, then remove to rack.