Preparation Steps

• Preheat oven to 350°F (175°C). Grease and flour a 9x13 inch baking pan.
• In a medium bowl, whisk together flour, baking soda, and salt.
• In a large bowl, cream together the softened butter and 1.5 cups of granulated sugar until light and fluffy.
• Beat in the eggs one at a time, then stir in the vanilla extract.
• Gradually add the dry ingredients to the wet ingredients, alternating with the sour cream, beginning and ending with the dry ingredients. Mix until just combined.
• In a small bowl, combine 0.25 cup granulated sugar and 1.5 teaspoons cinnamon for the swirl.
• Pour half of the cake batter into the prepared baking pan. Sprinkle half of the cinnamon-sugar mixture over the batter. Dollop spoonfuls of the remaining batter over the cinnamon sugar. Sprinkle the rest of the cinnamon-sugar mixture on top.
• Using a knife or skewer, gently swirl the cinnamon-sugar into the batter.
• 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 onto a wire rack to cool completely.