Preheat oven to 350°F. Line two light-colored baking sheets with parchment.
In a medium saucepan, melt the butter over medium heat, stirring frequently. Continue to cook until the butter foams and turns golden brown with a nutty aroma, about 5 minutes. Remove from heat, pour into a large mixing bowl, and let cool in the fridge for 30 minutes.
1 cup Butter
In a medium bowl, whisk together the oats, flour, baking soda, baking powder, cinnamon, cardamom, ginger, nutmeg, cloves, allspice, and salt.
2 cups Oats, 1 ¾ cups All-Purpose Flour, 1 teaspoon Baking Soda, ½ teaspoon Baking Powder, ½ teaspoon Salt, 1 ½ teaspoons Cinnamon, ½ teaspoon Cardamom, ½ teaspoon Ginger, ⅛ teaspoon Nutmeg, ⅛ teaspoon Cloves, ⅛ teaspoon All Spice
Add brown sugar and granulated sugar to the cooled butter. Beat with a hand or stand mixer on medium for about 2 minutes until light in color. Mix in the eggs one at a time, then the vanilla.
1 cup Brown Sugar, ½ cup Granulated Sugar, 2 large Eggs, 1 ½ teaspoons Vanilla Extract
With the mixer on low, slowly add the dry mixture. Scrape the sides and bottom of the bowl with a spatula, then mix for just a few seconds more to ensure everything is well incorporated without overmixing.
Use a cookie scoop to portion dough onto a parchment-lined sheet. Chill the dough on the sheet for 15 minutes.
Bake for 10–12 minutes, or until the edges are lightly golden.
Let the cookies cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.