Preheat your oven to 350°F (175°C). In a medium bowl, combine graham cracker crumbs, white sugar, and melted butter. Press firmly into the bottom of a 9-inch springform pan. Bake for 8-10 minutes until golden. Allow to cool.

In a large bowl, beat cream cheese until smooth. Gradually add confectioners’ sugar, milk, and vanilla, blending until fluffy. Fold in Cool Whip. Spread this filling over the cooled crust and refrigerate.

In a saucepan, mix cornstarch, sugar, and water over medium heat until smooth. Bring to a simmer, add raspberries, and cook 5-7 minutes until thickened. Stir in lemon juice, if using. Cool slightly.

Pour raspberry sauce over cheesecake filling, spreading evenly. Cover with plastic wrap and refrigerate for at least 4-6 hours to set.

Run a knife around the edge of the springform pan to release the cheesecake. Slice and serve chilled.