Preheat the oven to 350 degrees. Line a baking sheet with a silpat mat.
Whisk together the flour, baking powder, baking soda, and salt.
Scrape the seeds from the vanilla bean by placing the bean on a flat surface. Hold the bean flat with one hand, and split the bean in half lengthwise with a sharp knife. Use the backside of the paring knife’s blade to scrape the dark, moist pulp from the vanilla bean; this will prevent any strings from the vanilla bean pod in the seeds.
In a separate bowl, add the white sugar and the scraped vanilla bean seeds. Using your fingers, combine the sugar with the vanilla bean seeds until evenly distributed.
Add the brown sugar and butter to the bowl and beat using a hand mixer until creamy.
Add the egg and beat until combined.
Gradually add the flour mixture and oats to the butter mixture until just combined.
Drop by rounded teaspoonfuls onto the prepared baking sheet.
Place into the oven and bake for 8-10 minutes, or until brown around the edges and just set in the center.
Remove from the oven and let cool on the baking sheet for a few minutes before transferring them to a cooling rack.