In a large mixing bowl, combine ½ cup of softened butter, 1 cup of creamy peanut butter, 2 cups of powdered sugar, and 1 teaspoon of vanilla extract. Use an electric mixer on medium speed for about 2-3 minutes until the mixture is smooth and thick.

Line a 9x13-inch baking pan with parchment paper. Transfer the peanut butter mixture into the pan and press it firmly into an even layer using a spatula.

In a microwave-safe bowl, combine 2 cups of semi-sweet chocolate chips with 2 tablespoons of butter. Heat in the microwave in 30-second intervals, stirring after each interval, until melted and smooth, about 90 seconds.

Pour the chocolate ganache over the peanut butter layer and spread it evenly.

Place the assembled bars in the refrigerator and let them chill for at least 1 hour.

Remove the bars from the pan using the parchment paper, transfer them to a cutting board, and slice them into squares or rectangles.