Preparation Steps

• Preheat oven to 350°F (175°C). Grease and flour a 9x13 inch baking pan.
• In a medium bowl, whisk together the flour, baking soda, and salt.
  1.5 cups all-purpose flour
• In a large bowl, cream together the softened butter and granulated sugar until light and fluffy.
  1.5 cups all-purpose flour
• Beat in the eggs one at a time, then stir in the vanilla extract.
  1.5 cups all-purpose flour
• Gradually add the dry ingredients to the wet ingredients, alternating with the buttermilk, beginning and ending with the dry ingredients.
  1.5 cups all-purpose flour
• In a small bowl, combine the brown sugar and cinnamon for the swirl. Stir in the melted butter until well combined.
  1.5 cups all-purpose flour
• Pour half of the cake batter into the prepared pan. Sprinkle half of the cinnamon-sugar mixture over the batter. Dollop the remaining batter over the cinnamon-sugar. Sprinkle the remaining cinnamon-sugar mixture on top.
• Bake for 30-35 minutes, or until a wooden skewer inserted into the center comes out clean.
• Let the cake cool in the pan for 10 minutes before inverting it onto a wire rack to cool completely.