Preheat the oven to 350°F (175°C). Grease a 9×5-inch loaf pan and line with parchment for easy removal.
In a medium bowl, whisk together flour, baking powder, salt, cinnamon, and granulated sugar until evenly distributed.
In a separate bowl, whisk eggs, milk, melted butter (cool), vanilla, and optional sour cream or yogurt until smooth.
Pour the wet ingredients into the dry ingredients. Stir just until combined; a few lumps are okay. Avoid overmixing to keep the crumb tender.
If you’re using sour cream or yogurt, fold it in now for extra moisture. Transfer the batter to the prepared loaf pan, smoothing the top.
Bake for 55–65 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs. If the top browns too quickly, tent with foil after 40 minutes.
While the loaf bakes, mix the cinnamon sugar topping. When the bread is still warm, brush the top with a little melted butter and roll in the cinnamon-sugar mixture for a bakery-style crust.
Let the loaf rest in the pan for 10–15 minutes, then transfer to a rack to cool completely. If you prefer a glaze, drizzle the powdered sugar glaze over the cooled loaf.
Notes
A cozy Cinnamon Sugar Donut Bread recipe with a tender crumb, warm cinnamon aroma, and a cinnamon-sugar crust—perfect for breakfast, brunch, or a comforting snack.
