In a large bowl, combine the butter, light brown sugar, and white sugar.
Using an electric mixer, cream the ingredients together until well combined. This process will take 4 minutes. Start on slow speed and gradually speed up.
Here is the result.
Now add 1 egg at a time.
Mix well until all the ingredients are well incorporated.
Add the flour in 3 batches.
Combine the flour and the butter/sugar mixture. Do NOT over mix.
Here is the result.
Add the chocolate chips and walnuts.
Fold and mix them in. It's an arm workout.
Result.
Now using a large ice-cream scoop.
Scoop the cookie batter onto a plastic wrap. You want to form 8 large balls that resemble the size of a tennis ball. Yes, tennis ball. Alternatively, you can weigh them and form 8 balls. Each ball should be 6 ounces.
Wrap the cookie dough balls with plastic wrap and refrigerate for 12 hours.
The next day, place the cookie batter onto a baking tray. Make sure the cookie dough are at least 2 inches apart so they can spread. Bake at 375 degrees for 18-20 minutes. I baked my cookies for 19 minutes exactly. Do NOT overbake them so they remain gooey. Note: I baked 4 cookies, and froze the remaining 4 cookies for another time.
Once the cookies are out of the oven, LET THEM COOL FOR 10 MINUTES. They will firm up.
Indulge. Seriously, outrageously good.