Here’s what you will need:
3 tablespoons flour
4 tablespoons sugar
1 1/2 teaspoons cinnamon
2 cups all-purpose flour
1 teaspoon baking soda
1/2 teaspoon baking powder
1/4 teaspoon salt
1/2 cup unsalted butter, softened
1 cup sugar
1 (8 ounce) container sour cream
1 teaspoon vanilla
1 tablespoon sugar
1/4 teaspoon cinnamon
Let’s get baking:
Begin by preheating your oven to 350 degrees F. Grease and flour a 9×5-inch loaf pan; set aside.
In a small bowl, prepare the cinnamon swirl by whisking together the flour, sugar, and cinnamon. Set aside.
Then, for the bread, in a large bowl whisk together the flour, baking soda, baking powder, and salt.
In a medium size bowl, with a handheld (or electric mixer) beat the softened butter until light and airy, about three minutes. Add the sugar and beat again until combined, about four minutes. Next, add the eggs one at a time, incorporating the first one before adding the second. Finally, beat in sour cream and the vanilla.
Now gently incorporate the wet ingredients into the dry. Mix until just combined, being careful not to overmix. The final mixture will be more the consistency of a dough rather than runny like a cake batter.
Spread half of the mixture into the bottom of your greased and floured pan. Then evenly sprinkle your prepared cinnamon swirl over the top. Spread the remaining dough on top of the cinnamon swirl layer.
Finally, in a small bowl, mix together the sugar and cinnamon for the topping. Sprinkle this evenly over the top of the loaf.
Bake at 350 degrees F for 60-65 minutes. The loaf is done when a toothpick (or wood skewer) inserted near the center comes out clean.
Allow to cool in the pan for about 20 minutes. Gently run a butter knife around the edge of the pan to loosen the loaf. Remove from the pan to finish cooling.