Creating the Ultimate Chocolate Peanut Butter Ooey Gooey Cake is a delightful process. Follow these step-by-step instructions:

1. Preheat the Oven: Preheat your oven to 350°F (175°C). Grease and flour a 9×13 inch baking pan to prevent sticking.
2. Mix Dry Ingredients: In a large mixing bowl, combine the flour, sugar, cocoa powder, baking soda, baking powder, and salt. Whisk thoroughly to ensure even mixing.
3. Incorporate Wet Ingredients: Add the buttermilk, vegetable oil, eggs, and vanilla extract to the dry mixture. Mix well until just combined.
4. Add Boiling Water: Gradually stir in the boiling water until the batter is smooth. This step makes the cake incredibly moist.
5. Bake the Cake: Pour the batter into your prepared baking pan. Bake in the preheated oven for 30-35 minutes, or until a toothpick inserted in the center returns clean.
6. Cool the Cake: Once baked, remove from the oven and let the cake cool in the pan for 15-20 minutes before transferring it to a wire rack to cool completely.
7. Prepare the Peanut Butter Layer: In a medium bowl, combine peanut butter, powdered sugar, and milk. Mix until smooth and creamy.
8. Spread the Peanut Butter: When the cake is completely cool, spread the peanut butter mixture evenly over the top of the cake.
9. Add Chocolate Chips: Sprinkle semisweet chocolate chips on top of the peanut butter layer, allowing them to melt slightly from the warmth of the cake.
10. Drizzle Chocolate Sauce: For an extra touch of decadence, drizzle chocolate sauce over the top before serving.

These clear steps will guide you through creating this amazing dessert effortlessly.