Preheat the oven to 350°F (175°C). Grease a 9x13 inch baking pan.

In a mixing bowl, cream together the softened butter, granulated sugar, brown sugar, and peanut butter until smooth.

Add the vanilla extract and mix until combined.

In a separate bowl, whisk together the flour, baking soda, and salt.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined.

Spread the mixture evenly into the prepared baking pan.

Bake in the preheated oven for 20-25 minutes, or until the edges are golden brown.

Remove from the oven and let cool slightly.

If using, sprinkle chocolate chips over the top while still warm, then drizzle with peanut butter.

Allow to cool completely before cutting into bars.