• Preheat the oven to 350F then line a baking sheet with parchement paper and set aside.
• Cream the butter brown sugar, and granulated sugar together until combined. Add in the egg and vanilla and mix until light and fluffy.
• Mix in the flour, oats, cinnamon, nutmeg, baking soda, and salt, making sure to scrape the sides until the mixture is combined.
• Using a large cookie scooper, scoop out 8 equally sized cookie dough balls, place them on the prepared baking sheet, gently press down on the cookies to about 1 inch in thickness, and bake them in the preheated oven for 10 minutes. Make sure to not overbake them so they stay soft and gooey
• Let the cookies cool down on the baking sheet for 20 minutes then more to a cooling rack to cool down fully.

Make the glaze

• In a medium bowl, whisk the powdered sugar 1 tablespoon milk and vanilla together until combined. You can the mixture to be thick and creamy but thin enough to dip the cookies in. If it's too thick add 1 teaspoon milk at a time and mix.
• Dip the top of the cooled-down cookies into the vanilla sugar glaze then place them back on the cooling rack. Allow them to set fully before enjoying them!