Pistachio Paste

• Place the 1 ounce of pistachios (without the shells) in a food processor and pulse until they're as ground as they're going to get. Add 1-2 tsp of water to it and blend until it turns into a paste.
  1 ounce pistachios, 1-2 tsp water
• Preheat the oven to 350F (177C) convection OR 325F (163C) conventional and line two cookie sheets with parchment paper.
• In a small pot, over medium heat, cook the butter for 5-10 minutes, stirring intermittently until it begins to bubble and foam.
  1/2 cup (113g) salted butter
• Then stir continuously until you see the milk solids browning and settling on the bottom. Pour the butter into a bowl and allow it cool for a few minutes. 
• Add the light brown sugar to the warm butter and whisk together for about a minute.
  3/4 cup (150g) light brown sugar
• Add in the egg (or egg yolks), pistachio paste vanilla and whisk aggressively for 2-3 minutes, until it's smooth and has lightened in color.
  3 large egg yolks or 1 large egg, 2 Tbsp (30g) pistachio paste, 1 tsp vanilla bean paste
• Add the flour, baking powder and salt and fold the cookie dough just until there are a few streaks left of flour.
  1 cup (120g) all-purpose flour, 1 tsp baking powder, 1/4 tsp fine sea salt
• Fold in the chopped pistachios and chocolate, just until they're evenly dispersed.
  1 oz lightly salted pistachios, 4 oz dark chocolate
• Split cookie dough into 8 cookies (2.5 ounces each), (4-6 per cookie sheet, they spread a lot) and bake one sheet on the middle rack for 10 minutes, just until the edges are starting to brown.
• Remove them from the oven, give the pan a quick tap on the counter and use a round biscuit cutter to scoot them around so they’re perfectly round. Return to the oven for 2-3 more minutes and repeat. The edges should be lightly browned and the top no longer wet.
• Sprinkle with additional pistachios chunks and sea salt on top and allow them to rest for at least 10 minutes on the pan before transferring off the cookie sheet.
  pinch sea salt flakes