• gently melt the butter in a small heavy bottomed sauce pot until it starts to crackle, turn brown, and emit a nutty toasty flavor. This is your browned butter.
• Remove browned butter from the heat and allow it to cool until it becomes a spreadable texture-see notes above for more on this
• In a medium bowl mix together the flour, baking soda, salt, and espresso powder. Set aside.
• In a large bowl beat together the butter and sugars until light and fluffy
• Add the sourdough discard, vanilla extract and the vinegar until smooth. Add the egg and stir just until combined.
• Mix the flour mixture into the wet mixture just until combined. Stir in the chips.
• Allow these to rest in the refrigerator for at least 4 hours

To Bake

• Preheat oven to 350 degrees F
• Form cookies of desired size and place onto a parchment lined cookie sheet, about 3 inches apart.
• Bake for 10-12 minutes, until they look light brown around the edges, they will still look underdone in the center. Remove from the oven and immediately sprinkle each cookie with a little sea salt. Allow to sit on the sheet for 10 minutes before moving to a rack to cool.