In a bowl, combine flour and sugar; blend in butter with a wooden spoon until smooth. Press into an ungreased 13-in. x 9-in. x2-in. baking pan. Bake at 300 for 20-25 minutes or until set (crust will not be brown). Cool.
In a mixing bowl, beat cream cheese, confectioners sugar, vanilla and salt until smooth. Fold in whipped topping. Spread over crust. For topping, dissolve gelatin in boiling water; stir in raspberries. Chill for 20 minutes or until mixture begins to thicken. Spoon over filling. Refrigerate until set.
Cut into squares; garnish with whipped topping and mint if desired. Yield 12-16 servings.