Cream the Butter and Sugars: In a large mixing bowl or stand mixer, cream together the softened butter, brown sugar, and granulated sugar for 3-4 minutes until light and fluffy. Scrape down the sides of the bowl. Add the peanut butter and mix for 1 minute longer until fully incorporated.
Add Eggs and Vanilla: Add the eggs one at a time, mixing well after each addition. This ensures the eggs are fully incorporated and creates a smooth dough. Add the vanilla extract and mix until combined.
Mix in Dry Ingredients: Stir in the gluten-free rolled oats, baking soda, and salt. Mix until everything is evenly distributed throughout the dough. Fold in the milk chocolate chips.
Chill the Dough (Important!): I highly recommend chilling the dough for at least 30 minutes. For best results, chill it overnight (or for 24 hours) wrapped tightly in plastic wrap. Chilling the dough gives the cookies more loft and prevents them from spreading too thin while baking.
Preheat and Prepare: Preheat your oven to 350°F. Line a light-colored baking sheet with parchment paper or a Silpat mat for easier removal and even baking.
Scoop and Bake: Use a cookie scoop to drop cookie dough onto the prepared baking sheet, spacing them about 2 inches apart. Bake for 10-12 minutes until the edges are golden brown but the centers still look slightly underdone.
Cool and Enjoy: Let the cookies set up on the baking sheet for 5 minutes before transferring them to a wire rack. This allows them to finish cooking and prevents them from breaking apart. Enjoy warm or at room temperature!