Cook butter in a pan with medium heat. It will be sizzle and bubbly from the water content. After the moisture and the sound of the sizzle are gone, wait for 1-2 minutes until the milk solids from the butter turn brown and turn off the heat. Don't let the pan unattended or you will end up with burnt butter instead of brown butter. Set aside and let cool.
Heat oil in a pan, sauté pumpkin for 3 minutes. Add butter in the middle while the pumpkin is being cooked. Stir until pumpkin browned. Set aside and let cool.
After the browned butter is cooled, whisk browned butter, brown sugar, granulated sugar, egg, vanilla, and salt with a mixer for about 2-3 minutes until the mixture is fluffy.
Add ⅓ of the flour mixture and whisk with a mixer until just combined. Add the rest and whisk again until combined.
Add chocolate chips and cubed pumpkin and stir with a spatula until combined. Leave both a little for decoration.
Divide every 2 tablespoons of dough for each cookie. Flatten the dough a little by hand. Add chocolate chips and cubed pumpkin on top of every cookie dough from the rest chocolate chips and cubed pumpkin. Every cookie will be pretty. Put them on parchment paper.
Preheat oven to 350ºF or 175°C. Line baking sheet with parchment paper. Put the cookie dough balls 2 inches from each other so they will not stick when baked.
Bake for 10-12 minutes. After done baking, cool for 2-5 minutes before removing to wire racks to cool completely.
Pumpkin chocolate chips cookies are ready to serve. Enjoy!