Add <quantity>150<unit>g</unit></quantity> of butter to a small pot over medium heat. Cook until it starts to bubble, is light brown, and smells nutty

Pour the brown butter into another container, without adding the solids from the bottom of the pot. Refrigerate for 1h until it is solid

Add <quantity>100<unit>g</unit></quantity> of softened butter and <quantity>100<unit>g</unit></quantity> of the brown butter to a stand mixer bowl

Add <quantity>150<unit>g</unit></quantity> of brown sugar and <quantity>80<unit>g</unit></quantity> of white sugar. Mix using the paddle attachment on medium speed until the mixture starts to get fluffy

Add <quantity>2</quantity> eggs, <quantity>1</quantity> at a time, and mix on high speed until smooth

Combine <quantity>360<unit>g</unit></quantity> of all-purpose flour, <quantity>5<unit>g</unit></quantity> of cornstarch, <quantity>5<unit>g </unit></quantity> of salt, and <quantity>5<unit>g</unit></quantity> of baking powder in a bowl

Add the dry ingredients to the wet ingredients and mix just until everything comes together

Add <quantity>130<unit>g</unit></quantity> of 50% chocolate chips, <quantity>130<unit>g</unit></quantity> of 70% chocolate chips, and <quantity>30<unit>g</unit></quantity> of chopped cashew nuts. Mix by hand until evenly distributed

Use an ice cream scoop to make balls of about <quantity>80<unit>g</unit></quantity> and place them on a silicone mat <quantity>5<unit>cm</unit></quantity> apart

Roll the balls by hand until they are mostly round. Place them in the freezer until they are completely frozen

Preheat an oven to <temperature>180<unit>°C</unit></temperature>

Bake the cookies for 15 until dark brown and fully cooked. The brown butter cookies are ready

Enjoy them however you like!