In a medium skillet over medium heat, melt the butter. Stir constantly until the butter turns brown with a nutty aroma. Remove from heat and pour into a large heat-proof bowl. Let it cool completely.

Set your oven to 350°F (175°C) and line a baking sheet with parchment paper.

Spread the pumpkin puree on a plate and press paper towels firmly to absorb excess moisture.

Add the brown sugar, granulated sugar, blotted pumpkin, egg yolks, and vanilla extract to the cooled brown butter. Mix well until combined.

In a separate bowl, whisk together the all-purpose flour, pumpkin spice, baking soda, baking powder, and salt.

Gradually add the dry ingredients to the wet mixture, stirring until fully combined.

Gently stir in the old-fashioned oats until evenly distributed in the dough.

Using a cookie scoop, portion out 3-tablespoon-sized balls of dough. Optionally, roll them for uniformity and place them on the prepared baking sheet.

Bake in the preheated oven for 12 minutes. The cookies will look slightly underbaked; this is perfect for a soft texture.

Let the cookies cool on the baking sheet for 5-10 minutes before transferring them to a cooling rack.

In a bowl, whisk together the powdered sugar, brown sugar, milk, corn syrup, and vanilla extract until smooth and creamy.

Drizzle the glaze over the cooled cookies and allow it to set before serving. For a festive touch, consider sprinkling some chopped nuts or pumpkin seeds on top before the glaze sets!