Step 1

Preheat oven to 350°F (177°C). Spray a 9×5 inch loaf pan with nonstick spray.

Step 2

Mix the 1/2 cup (100g) granulated sugar and 1 Tablespoon of ground cinnamon together.

Step 3

Whisk the flour, baking soda, and salt together in a large bowl. In a medium bowl, whisk the egg and 3/4 cup (150g) granulated sugar together until combined. Whisk in the oil, sour cream, milk, and vanilla extract. Pour the wet ingredients into the dry ingredients, then whisk to completely combine. Avoid over-mixing. You will have about 3 cups of batter.

Step 4

Pour/spread half of the batter into prepared loaf pan. Sprinkle almost all of the cinnamon sugar evenly on top (reserve about 2 Tablespoons for topping). It’s a very thick layer of cinnamon sugar. Carefully pour/spread remaining batter evenly on top. The top layer of batter will want to stick to the cinnamon sugar filling, making spreading a little tougher to do, but use a spoon to carefully spread it out as best you can. Sprinkle with the rest of the cinnamon sugar. Using a knife, make a large swirl down the loaf pan, as shown in the video tutorial above. Avoid over-swirling, which will mix the layers together too much.

Step 5

Bake the bread for 50 minutes to 1 hour, covering loosely with foil about halfway through to prevent the top from over-browning. Poke the center of the bread with a toothpick. If it comes out clean, the bread is done. Oven times will vary between ovens. My bread usually takes 55 minutes. Cool bread completely in the pan set on a wire rack.

Step 6

Drizzle with icing, if using. Slice and serve. Cover and store leftover bread at room temperature for 1 day or in the refrigerator for up to 1 week.