1-Gathering and Preparing Ingredients: First, make sure all your ingredients are at room temperature to help them mix smoothly. Preheat your oven to 350°F (177°C) and grease a loaf pan with nonstick spray. This step sets the foundation for even baking and prevents sticking.

2-Mixing the Batter: In one bowl, whisk together the dry ingredients: 2 cups all-purpose flour, 1 teaspoon baking soda, and 1/2 teaspoon salt. In another bowl, beat 1 large egg with 3/4 cup granulated sugar, then stir in 1/3 cup vegetable oil, 1/3 cup sour cream or plain/Greek yogurt, 2/3 cup whole milk, and 1 and 1/2 teaspoons pure vanilla extract.

3-Mixing the Batter: Combine the wet and dry mixtures gently, just until incorporated, to avoid over-mixing which can make the bread tough. For the cinnamon swirl, mix 1/2 cup granulated sugar with 1 tablespoon ground cinnamon in a separate bowl.

4-Baking and Cooling: Pour half the batter into the pan, sprinkle most of the cinnamon sugar on top, add the rest of the batter, and finish with the remaining cinnamon sugar. Use a knife to swirl it gently once. Bake for 50-65 minutes, covering with foil halfway through to prevent over-browning. Test for doneness with a toothpick, then cool in the pan for one hour before moving to a wire rack.

5-Baking and Cooling: Optionally, drizzle with simple icing for extra appeal. Prep time is about 20 minutes, cook time around 55 minutes, and total time roughly 2 hours including cooling, yielding 1 loaf.

6-Adaptations for Variations: If you’re making vegan or gluten-free versions, adjust as noted earlier and keep an eye on baking time, as these might need slight tweaks. This bread has a softer texture than fruit-based quick breads, with prominent vanilla and cinnamon flavors you can enhance with additions like chopped apples or nuts.