Step 1

Heat oven to 350°F. Spray 9- or 10-inch fluted tube cake pan with cooking spray.

Step 2

In large bowl, mix flour, sugar, baking powder, baking soda and salt. Add peanut butter and 3/4 cup of the buttermilk. Beat on medium-high speed until smooth and creamy, scraping bowl as needed.

Step 3

In separate bowl, mix remaining 1/2 cup buttermilk with the eggs and vanilla. Add to peanut butter mixture in 3 additions, mixing after each.

Step 4

Scoop out approximately 1 cup of the peanut butter cake batter into medium bowl. Add melted chocolate; mix until combined.

Step 5

Spoon one-third of the peanut butter cake batter into cake pan. Spoon the chocolate-peanut butter cake batter on top, and then top with the remaining peanut butter cake batter. Use a knife to gently swirl batters together.

Step 6

Bake 50 to 60 minutes or until toothpick inserted in center comes out clean. Cool 15 minutes in pan; remove to cooling rack to cool completely.

Step 7

To make glaze, place chocolate in small bowl. Microwave cream in small microwavable bowl uncovered on High just until hot, then pour over the chocolate. Let stand 5 minutes; stir until smooth. Drizzle over cooled cake; let stand 20 minutes to set.