1. In a saucepan or microwave-safe bowl, melt the butter, stir in the sugar. Heat until the mixture is just beginning to bubble. Remove from burner or microwave, transfer to a medium bowl, and allow to cool to lukewarm.
2. Stir in vanilla, salt, baking soda, espresso powder (if using), baking powder, corn syrup, and vinegar. Add eggs, beating well after each addition, then the flour, stirring to combine, and finally mix in the chips. Cover the dough and refrigerate overnight.
3. Preheat oven to 350°F. Lightly grease two baking sheets, or line them with parchment paper.
4. Drop the dough by tablespoonfuls onto prepared cookie sheet. Bake two sheets at a time, reversing the pans midway through, until they are just beginning to brown around the edges, 12 to 13 minutes. Remove from cookie sheets, place on cooling rack.