1 cup (2 sticks) unsalted butter, room temperature
1 cup light or dark brown sugar, tightly packed
1/2 cup white sugar
2 eggs
2 teaspoons vanilla extract
Process
Heat oven to 375 F.
Sift flour, baking soda, and salt in a small bowl. Set aside.
Mix together chocolate chips and chopped nuts in a small bowl. Set aside.
Cream the butter and sugars until well mixed and light. Scrape down the sides. Add eggs and vanilla. Mix only until combined. Scrape down the sides.
Add about 1/3 the flour mixture, and mix just until combined. Repeat with the 2/3rd. For the final 3rd, add the four and chocolate chip/nut mixture. They will get a bit crushed. That's okay. Mix until there's barely a trace of flour visible. Don't over-mix.
Set up a sheet pan with a silpat or parchment paper. Bake one tray at a time or they will all cook at different rates. Make them spherical, not flat. The cookie size is up to you. I use a large ice cream scoop, or if I'm making them for lunch kits, two small ice cream scoops together.
Leave a few inches between the raw cookies. Place sheet pan in the oven. Cook for 8-10 minutes, depending on the size of cookie.
Put remaining dough in an airtight container, and keep in the fridge for up to a few days.