Preheat oven to 350°F. Grease one 9x5-inch loaf pan with solid vegetable shortening or Wilton Cake Release.
In a small bowl, combine ⅓ cup brown sugar, nuts, and cinnamon.
In a large bowl, combine sugar, flour, baking powder, and salt.
In another bowl, beat egg with a fork; stir in milk. vanilla, and oil. Stir in peanut butter.
Add egg mixture to flour mixture all at once and stir until just moistened. The mixture will be thick and lumpy. Don't over-stir. Over-stirring will make the bread tough.
Pour half the batter into the prepared pan. Sprinkle all the cinnamon mixture. Pour remaining batter on top.
Bake 40 to 45 minutes or until toothpick inserted in center comes out clean. Cool in pan 10 minutes then remove to a wire rack to cool completely before slicing. Makes one loaf.