Preheat oven to 400°F. Line baking sheet with parchment paper or silpat.

Set aside ¼ cup of chocolate chips. Add the rest of the semi-sweet chocolate chips and ¼ cup (½ stick) of butter to the microwave-safe bowl. Microwave, stirring occasionally, until the chocolate is melted.

In a large bowl, whisk together flour, baking powder, baking soda, salt, and rolled oats. Set aside.

To the bowl of a stand mixer, add the remaining butter and brown sugar. Beat on low until smooth. Add melted chocolate, eggs, and vanilla. Mix until fully incorporated. Slowly add the dry ingredients until fully incorporated.

Using a cookie scoop, portion dough, then roll into a ball. Place on a baking sheet, then slightly flatten the cookies. Top with the reserved chocolate chips.

Bake for 7-8 minutes. Cookies may look underdone. Allow to cool slightly, then transfer to wire rack.