1 large egg 1/2 cup unsalted butter (1 stick) 1/2 cup light brown sugar, packed 1/4 cup granulated sugar 1 tablespoon vanilla extract 1 cup old-fashioned whole rolled oats (not instant or quick cook) 1 cup all-purpose flour 1/2 cup sweetened shredded coconut 1/2 cup chopped walnuts (pecans may be substituted; or nuts may be…