Melt the butter in a saucepan over medium heat. For brown butter cookies, continue cooking until the butter turns golden brown and smells nutty. Remove from heat and cool for several minutes.

In a large bowl, whisk together the cooled melted butter, brown sugar, and granulated sugar until smooth.

Add the pumpkin puree, egg yolk, and vanilla extract. Whisk until well combined.

In a separate bowl, whisk together the flour, baking soda, salt, cinnamon, nutmeg, ginger, and optional cloves.

Gradually add the dry ingredients to the pumpkin mixture. Stir gently until just combined.

Fold in the chocolate chips and optional chopped nuts. Do not overmix the dough.

Cover the dough and refrigerate for 30–45 minutes.

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

Scoop rounded tablespoons of dough onto the prepared baking sheet, leaving several inches between each cookie.

Bake for 10–13 minutes, or until the edges are set while the centers still look slightly soft.

Press a few extra chocolate chips onto the warm cookies if desired.

Let the cookies cool on the baking sheet for about 5 minutes, then transfer them to a wire rack.