If you turn this bread out of the pan to cool, some of the streusel topping will fall off. Instead, line the pan with heavy-duty aluminum foil, and you'll be able to easily lift out the bread.
Vegetable cooking spray
1 large egg
1 cup firmly packed light brown sugar
2 tablespoons creamy peanut butter
2 tablespoons butter, melted
2 cups all-purpose flour
1 teaspoon baking powder
1/2 teaspoon baking soda
1/2 teaspoon salt
1 cup buttermilk
3/4 cup semisweet chocolate mini-morsels
Peanut Streusel Topping
How to Make It
Preheat oven to 350°. Line bottom and sides of a 9- x 5-inch loaf pan with heavy-duty aluminum foil, allowing 2 to 3 inches to extend over sides. Lightly grease foil with cooking spray.
Beat egg and sugar at medium speed with an electric mixer 2 minutes or until creamy; add peanut butter and butter, beating until blended.
Stir together flour and next 3 ingredients in a medium bowl; whisk in egg mixture and buttermilk just until blended. (Batter will be slightly lumpy.) Stir in mini-morsels.
Spoon about 2/3 cup Peanut Streusel Topping on bottom of prepared pan. Spoon half of batter over streusel, gently spreading batter to sides of pan to cover streusel. Repeat procedure once. Sprinkle remaining 2/3 cup Peanut Streusel Topping over batter, gently pressing topping into batter.
Bake at 350° for 1 hour and 5 minutes or until a long wooden pick inserted in center comes out clean, shielding with foil after 45 minutes, if necessary. Cool in pan on a wire rack 10 minutes. Lift loaf from pan, using foil sides as handles. Place loaf on a wire rack. Carefully pull down sides of foil. Cool loaf completely (about 1 hour).