1️⃣ Prepare the oat mixture
Pulse oats in a food processor for a few seconds to break them down slightly. In a bowl, whisk together oats, flour, baking powder, salt, cinnamon, and nutmeg.

2️⃣ Mix the wet ingredients
In a separate bowl, beat butter, brown sugar, and granulated sugar until fluffy. Add eggs and vanilla, mixing until fully incorporated.

3️⃣ Combine and chill
Gradually mix dry ingredients into the wet mixture until just combined. Cover and chill the dough for 30 minutes to enhance flavor and prevent spreading.

4️⃣ Shape and bake
Preheat oven to 350°F (175°C). Roll tablespoon-sized portions of dough into balls and place them 2 inches apart on a parchment-lined baking sheet. Bake for 10–12 minutes until edges are golden brown. Let cool for 5 minutes, then transfer to a wire rack.

5️⃣ Make the icing and glaze
Whisk powdered sugar, milk, and vanilla until smooth. Drizzle or dip the cooled cookies in the icing and let set for 15 minutes.