In a medium skillet, melt butter over medium-low heat, stirring nearly continuously. Butter will melt, then begin to foam. It will then begin to turn golden brown and smell nutty. As soon at the butter begins to turn brown, take the pan off the heat, and continue to stir for about 1 minute, to ensure carryover heat doesn't continue to cook and subsequently burn the already browned butter. Transfer to a small bowl, cover with plastic wrap, and let cool to room temperature, about 1-2 hours.
1 stick unsalted butter
Preheat oven to 350ºF.
When the butter has cooled down and started to solidify slightly, add the butter to a large mixing bowl. Add the sugars, and cream the butter and the sugars until very light and fluffy, about 5-7 minutes on medium high. Scrape down the side of the bowl.
2 tablespoons white sugar, 1 cup dark brown sugar
Continue mixing and add the egg and egg yolk one at a time. Add the vanilla. Scrape down the bowl with a spatula. Combine the flour, soda and salt in another bowl with a whisk to combine. With the machine on low, slowly add the flour. Mix until just combined, taking care not to over mix.
1 egg + 1 egg yolk, 1 teaspoon vanilla, 1 1/2 cup all-purpose flour, 3/4 teaspoon baking soda, 1/4 teaspoon salt
With a spatula, fold in the white chocolate and pistachios. Refrigerate dough for at least one hour 1 hour, or up to 5 days. I made this dough four days before I baked it, and the dough was so flavorful and delicious! I recommend letting this dough refrigerate for at least a few hours before baking to let the dough develop the most decadent flavor.
8 oz. white chocolate, 1/2 cup pistachios
Use a medium-sized cookie scoop to form cookies and sprinkle a very fine dusting of good quality sea salt on top, if desired.
1/2 teaspoon flaky sea salt
Bake at 350ºF for 12 minutes. They should be lightly golden on the outside but still look gooey on the inside.