Preheat oven to 350°F (175°C). Grease and flour a cake pan.

In a mixing bowl, cream together peanut butter and sugar until fluffy.

Beat in eggs one at a time, then add vanilla extract.

In a separate bowl, sift together cocoa powder, baking powder, and salt.

Gradually add dry ingredients to the peanut butter mixture, alternating with milk.

Fold in chocolate chips.

Pour batter into the prepared pan and bake for 30-35 minutes or until a toothpick inserted comes out clean.

Let cool before serving.