Preheat the oven to 325°F and grease a 9-inch springform pan.

In a large bowl, combine flour, baking powder, baking soda, and salt.

In a large mixing bowl, beat sugar and butter until creamy.

Add vanilla and eggs, beating well.

Add flour mixture to the mixing bowl, alternately with sour cream, beating until all ingredients are just moistened — do not overmix.

Fold in peanut butter chips and 1 cup mini semi-sweet chocolate chips.

Pour batter into springform pan.

Prepare topping.

In a small bowl, combine brown sugar, flour, and butter, cutting with a knife or pastry blender until crumbly.

Fold in peanuts, peanut butter chips, and remaining mini semi-sweet chocolate chips.

Sprinkle crumb topping over batter in the springform pan.

Bake for 65-75 minutes, or until a toothpick inserted near the center comes out clean.

Remove to a wire rack to cool.

Release sides of springform pan.

Transfer coffee cake to a serving platter.

Drizzle with melted peanut butter.

Cut and serve.