½cup(125g)milk (preferably not skim milk - I use 2% milk)
½cup(120g)sour cream (see note)
⅓cup(70g)vegetable or canola oil
1largeegg
1teaspoonvanilla extract
1 ¾cups(249g)all-purpose flour
1teaspoonbaking powder
½teaspoonbaking soda
½teaspoonsalt
Cinnamon Sugar + Topping:
6tablespoons(80g)granulated sugar
2 ½teaspoonsground cinnamon
1tablespoonmelted butter
Instructions
Preheat the oven to 350 degrees F. Grease an 8 1/2-X4 1/2-inch loaf pan with nonstick cooking spray. Optional: line pan with parchment and grease parchment.
For the batter, in a large bowl, add the sugar (3/4 cup), milk, sour cream, oil, egg, and vanilla. Mix well.
Add the flour, baking powder, baking soda and salt. Mix until no dry streaks remain (don't over mix).
For the cinnamon and sugar, in a small bowl, mix the granulated sugar (6 tablespoons) and cinnamon together until well-combined.
To assemble, spread half of the batter in the prepared loaf pan. Sprinkle 1/4 cup of the cinnamon/sugar mixture over the batter.
In large spoonfuls, dollop the remaining batter over the cinnamon and sugar. Spread evenly.
Sprinkle remaining cinnamon and sugar (about 2 1/2 tablespoons) evenly over the top of the batter.
Draw a butter knife through the batter in three diagonal lines starting from one corner in a down-up-down pattern and then repeat the pattern one more from an opposite corner so the lines cross each other (see the pictures in the post for a visual). Don't over swirl the batter. It just needs a few slashes for optimal cinnamon and sugar swirling.
Drizzle the melted butter across the top of the bread.
Optional: the batter fills an 8 1/2-X4 1/2-inch pan about 2/3 full. If you live at high elevation or are worried about any of the cinnamon topping dripping into your oven while baking, place the loaf pan on a sheet pan to bake. FYI: I live at 2,500 feet elevation, and the bread doesn't overflow/drip in my oven.
Bake the bread for 50 to 55 minutes. The bread won't dome as much as other quick breads and may be relatively flat across the top, but a toothpick inserted in the center should come out clean or with moist crumbs. Add additional time, if needed.
Let the bread cool for a few minutes in the pan and then gently turn out (or lift parchment paper to remove) and let cool completely on a cooling rack.
Because the top of the bread will have some crunch to it, for neat slices, use a sharp serrated knife and gently slice the corner edge of the bread before drawing the knife across to cut all the way through each slice.
Notes
Sour Cream Substitute:This bread works well subbing in 1 cup buttermilk in place of the 1/2 cup milk + 1/2 cup sour cream. The crumb is a bit tighter with the milk/sour cream, but the bread is ultra-moist and delicious either way.Mini Loaf Pans:Baking this bread in mini loaf pans is a bit tricky because the amount of batter is a bit too much for two standard mini loaf pans and not quite enough for three mini loaf pans. If you want to bake in mini loaf pans, I'd suggest using three pans (knowing the baked loaves won't be quite as tall as other mini loaf pan quick breads). For three mini loaf pans, you'll use about 260 grams of batter per pan (divided in half to allow for the cinnamon/sugar layer) and about 1 1/4 tablespoons cinnamon/sugar mixture per pan (divided between the middle layer and the top). Drizzle each mini loaf with a teaspoon or so of butter before baking.