01 -  Preheat the oven to 350°F (175°C). Line a baking sheet with parchment paper or a silicone baking mat. 
 02 -  In a medium bowl, whisk together the flour, baking powder, salt, cinnamon, and nutmeg. 
 03 -  In a large bowl, cream the softened butter and brown sugar with a hand mixer or stand mixer until light and fluffy (about 2–3 minutes). 
 04 -  Beat in the egg, vanilla extract, and maple syrup until smooth and well combined. Gradually add the milk, mixing until fully incorporated. 
 05 -  Add the dry ingredients to the wet mixture in two parts, mixing on low speed until just combined. 
 06 -  Stir in the rolled oats until evenly distributed, then fold in the white chocolate chips. 
 07 -  Scoop rounded tablespoons of dough onto the prepared baking sheet, spacing them about 2 inches apart. Gently flatten each dough ball slightly with your fingertips. 
 08 -  Bake for 10–12 minutes, or until edges are golden and centers are just set (do not overbake). 
 09 -  Remove from the oven and let cookies cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely. 
 10 -  Store cooled cookies in an airtight container at room temperature for up to 1 week.