Preheat your oven to 350°F (175°C).
Grease your baking pan with a bit of butter or line it with parchment paper.
In a large mixing bowl, beat the unsalted butter and light brown sugar together until light and fluffy, about 2-3 minutes.
Mix in the vanilla extract until evenly incorporated.
In a separate bowl, whisk together the oats, baking soda, salt, and flour until well combined.
Gradually add the dry mixture to the butter-sugar mixture, stirring until just combined.
Gently fold in the cookie butter until evenly distributed.
Fold in the milk chocolate chips.
Transfer the batter to your prepared baking pan and spread it evenly.
Bake for 25-30 minutes or until the edges are golden brown and a toothpick inserted in the center comes out clean.
Allow to cool in the pan for about 10 minutes, then transfer to a wire rack to cool completely. Cut into squares and enjoy!
