Set aside 2 tablespoons cookie crumbs for garnish. In a small bowl, combine remaining crumbs with enough hot water to make crumbs spreadable. Spread over the graham cracker crust; set aside.
In a large bowl, beat cream cheese until fluffy. Beat in the sugar, milk and extract until smooth. Fold in whipped topping.
If food coloring is desired, divide mixture in half and add coloring to one half. Alternately spoon mounds of plain and colored mixture into crust; swirl with a knife. Sprinkle with reserved cookie crumbs. Cover and refrigerate for 3 hours or until firm.