In a microwave-safe bowl, combine ½ cup of butter, 1 cup of creamy peanut butter, and 1 teaspoon of vanilla extract. Microwave on high for 90 seconds, then stir until smooth and creamy. Gradually mix in 2 cups of powdered sugar until fully combined. Grease an 8-9 inch pan or line it with parchment paper, then firmly press the peanut butter mixture evenly into the prepared pan.

In a separate microwave-safe bowl, combine 1 cup of sweetened condensed milk, 1 ½ cups of dark chocolate chips, and an additional 2 tablespoons of butter. Heat in the microwave for 90 seconds, stirring well to achieve a smooth consistency. If needed, continue microwaving in short bursts of 15 seconds until completely melted. Pour the chocolate mixture over the peanut butter layer and spread it out evenly with a spatula.

Allow the fudge to cool at room temperature for at least 4 hours, or place it in the refrigerator to speed up the setting process. Once firm, gently lift the fudge from the pan using the parchment paper, if used. Slice into bite-sized squares for serving, ensuring sharp cuts for clean edges. Store any leftovers in an airtight container in the fridge, where it will keep fresh for up to a week.