Preheat the oven to 350°F with the rack in the highest position. Line a baking sheet with foil or a silicone liner.
Combine the butter and brown sugar in a medium glass mixing bowl and heat in the microwave until melted (about 1 minute). Whisk to combine, then add the chocolate chips. Heat the chocolate chips in 30-second bursts in the microwave until melted. (Alternatively, melt the butter and the chocolate in a double boiler on the stove top.) Whisk well and let cool for 5 minutes.
Beat in the eggs one at a time, whisking vigorously until thick and glossy. Use a rubber spatula to stir in the dry ingredients just until combined. The dough will be stiff and easy to handle.
Eat right away or wrap each cookie ice cream sandwich in wax paper or plastic wrap and store in the freezer. Let soften slightly at room temperature before eating, about 10 minutes.
Copyright 2021 Lynne Curry