Preheat your oven to 350°F (175°C). Line a 9x13-inch baking pan with foil and coat it with nonstick cooking spray to ensure easy removal later.

In a large bowl, combine the melted butter with both sugars and stir until smooth. Add the eggs, one at a time, mixing well after each addition. Stir in the vanilla extract, salt, and baking soda. Gradually add the flour, mixing until fully combined. Fold in the chocolate chips.

In a small bowl, mix the sweetened condensed milk with the creamy peanut butter until you have a smooth mixture.

Press half of the cookie dough evenly into the prepared pan. (Tip: Spray your hands lightly with cooking spray to prevent sticking.)

Arrange the peanut butter cups in a single layer over the cookie dough base.

Pour the sweetened condensed milk mixture evenly over the peanut butter cups, leaving about a 1/4-inch border around the edges to prevent the mixture from touching the foil.

Break up the remaining cookie dough into pieces and place them over the top layer. Flatten gently with your hands; it will mostly but not completely cover the peanut butter filling.

Bake the bars for 30-35 minutes, or until the tops are lightly golden brown. Let the bars cool completely in the pan before slicing into squares or rectangles.

Store the bars in an airtight container at room temperature for up to 3 days, or freeze them for up to one month. These bars are best served at room temperature.