Prep Cinnamon Swirl: Combine 2.5 teaspoons of ground cinnamon, 2 tablespoons of brown sugar, and 1/4 cup of granulated sugar in a small bowl.

Mix Dry Ingredients: In a large bowl, whisk together 2 cups of all-purpose flour, 1 cup of granulated sugar, 1 teaspoon of baking soda, and 1/2 teaspoon of salt.

Mix Wet Ingredients: In another bowl, whisk together 1 cup of buttermilk, 1 large egg, 1/4 cup of canola oil, and 1 teaspoon of butter extract if using.

Combine Ingredients: Pour the wet mixture into the dry ingredients, stirring gently until just moistened.

Layer in Pan: Grease a 9x5 inch loaf pan. Pour half the batter into the pan, sprinkle 2/3 of the cinnamon sugar mixture, add remaining batter, and the rest of the cinnamon filling.

Swirl: Use a butter knife to gently swirl the cinnamon mixture through the batter.

Bake: Preheat oven to 350°F (175°C) and bake for 50-60 minutes, until golden brown and a toothpick comes out clean.

Cool: Remove from oven, cool for at least 20 minutes in the pan, then transfer to a wire rack.

Glaze (optional): Mix 1/2 cup confectioners' sugar with 1-2 tablespoons milk and 1/2 teaspoon vanilla extract until smooth, then drizzle over cooled bread.