Whisk cookie crumbs, sugar, flour, egg whites, milk, butter, vanilla extract, and salt together in a large bowl until batter is smooth.
Heat an oiled griddle over medium-high heat. Drop batter by large spoonfuls onto griddle and cook until edges are set, 4 to 5 minutes. Flip and continue to cook until disc is firm, 1 to 2 minutes.
Roll disc into a cone shape. Prop up the disc in place for 1 to 2 minutes until hardened into a cone. Repeat with remaining batter.
