• Preheat oven to 350°F and spray a 9x5 loaf pan with baking spray or line it with parchment paper sprayed with baking spray.
• Combine the flour, baking soda, cinnamon, baking powder, and salt in a medium sized bowl and set aside
  2 cups all-pupose flour, 1 tsp baking soda, 1/4 tsp baking powder, 1/2 tsp ground cinnamon, 1/4 tsp fine sea salt
• Beat butter, sugar, and brown sugar for about 2 minutes until it is creamed together.
  1/2 cup unsalted butter, 1/2 cup granulated sugar, 1/2 cup light brown sugar
• Add eggs and mix followed by the buttermilk and vanilla. Mix until well combined.
  1 large egg, 1 cup buttermilk, 1 tsp vanilla extract
• Add dry ingredients and mix just enough to combine all ingredients.
• Pour 1/2 the batter into the loaf pan, making sure to spread it out evenly. Sprinkle 2/3 of the cinnamon sugar mixture over the batter. Pour the remaining batter over the cinnamon sugar layer, level it out and top with remaining cinnamon sugar.
• Using a butter knife, gently swirl the top of the batter
• Bake for 40 - 45 minutes until a toothpick inserted in the center comes out clean. Allow loaf to cool in the pan for 10 minutes, then remove loaf from pan and let cool completely on a wire rack

Cinnamon Sugar

• In a small bowl, mix the sugar and cinnamon together to use for the filing and topping.
  1/3 cup granulated sugar, 1 tsp ground cinnamon