01 -
Turn on your oven to heat up at 350°F. Lightly coat a 1-pound loaf pan (8.5x8.4) with baking spray.
02 -
Stir together the cinnamon, the 1/3 cup sugar, and the walnuts in a small bowl.
03 -
Take a big bowl and blend together the rest of the sugar, salt, flour, and baking powder.
04 -
Combine the egg, sour cream, milk, vanilla, and oil in a medium-sized bowl. Whisk together until smooth.
05 -
Pour the wet mix into the dry ingredients and gently stir. It's okay if there are some small lumps.
06 -
Spoon half of the batter into the oiled pan. Sprinkle with half the nut-and-cinnamon mix. Add the rest of the batter followed by the remaining swirl mixture on top.
07 -
Drag a butterknife through the layers once to create a marbled effect in the batter.
08 -
Bake it for 60 to 67 minutes. It's ready when a toothpick in the middle comes out clean. Cover the top with foil partway through if it's browning too fast.
09 -
Let the bread cool all the way before slicing and serving it.