In a medium saucepan over medium heat, melt the butter. Continue to cook the butter, swirling the pan occasionally, until it foams and froth. The butter will begin to sputter and crackle. Allow the butter to become fragrant with brown bits beginning to form on the bottom of the pan. Once the bits are amber brown, remove the pan from heat and pour the butter into a small heatproof bowl. Be careful not to let the butter burn. Allow to cool until just warm, about 20 minutes.

Preheat the oven to 350°F. Line large baking sheets with nonstick baking mats or parchment paper.

In a small bowl, combine the flour, baking powder, baking soda, salt, and oats.

In the bowl of an electric mixer, beat the brown sugar, granulated sugar, and cooled butter into very well combined, about 3 minutes. Beat in the Biscoff. Add in the egg and vanilla and beat until combined. On low speed gradually add the flour mixture and beat until just combined. Beat in the chocolate chips.

Drop 3-tablespoon sized balls of dough onto the prepared baking sheets. Bake for 10 to 12 minutes, or until golden brown at the edges. Let cool on a wire rack.