Instructions:

• Heat butter in a large saucepan over medium heat. Whisk constantly. Butter will crackle, then foam. Watch your pan carefully. Within a couple minutes, the butter will turn a golden amber color and give off a nutty aroma. As soon as it turns golden brown, remove from heat. Pour into a medium bowl and let cool for 10-15 minutes until cool enough to handle.
• Using an electric mixer, cream the butter and sugars until fluffy and well combined. Add in the egg, egg yolk, vanilla, yogurt, and espresso powder. Mix well – approximately 2 minutes.
• In separate bowl, whisk together flour, baking soda, and salt. Turn mixer on low and gradually add the dry ingredients to the wet ingredients until just combined.
• Add semi-sweet and dark chocolate chips and stir until just combined. Don’t overmix.
• Chill dough for 10 minutes.
• Scoop cookie dough onto cookie sheets lined with parchment paper. Use a medium cookie scoop or measure out dough 2 Tbsp. for each cookie. Place 2 inches apart.
• This is important! Chill cookie dough for an additional 2-12 hours in the refrigerator. The brown butter needs time to solidify. If you bake the cookies immediately, they will flatten out and spread all over.
• Preheat the oven to 350°F. Pull cookie sheets out of the refrigerator and immediately place into the oven.
• Bake the cookies for 9-11 minutes until the edges of the cookies begin to turn golden brown. Cool the cookies on the sheets for 5 minutes to allow for carryover cooking. Sprinkle each with a pinch of flaky sea salt.
• Transfer the cookies to wire racks to cool completely. Makes 24-30 cookies.