Preheat oven to 350F. Line baking sheet with parchment paper or silicone mat.

In a microwave-safe bowl, melt the butter and peanut butter together for about 1 minute, stirring until smooth. Let cool slightly.

In a large bowl, whisk together the egg, brown sugar, granulated sugar, and vanilla until combined.

Add the melted butter mixture to the egg mixture and stir well.

Stir in the oats, flour, baking soda, and salt until just combined. Do not overmix.

Fold in the chocolate chips and peanut butter chips.

Use a cookie scoop or your hands to form dough balls, place them on the prepared baking sheet, and flatten slightly.

Bake for 11-12 minutes, or until edges are lightly golden but centers are soft.

Allow cookies to cool on the baking sheet for 10 minutes before transferring to a wire rack.