In a saucepan over medium heat, combine cornstarch and powdered sugar. Add fresh raspberries, a splash of water, and lemon juice. Stir continuously for 5-7 minutes until thickened.

In a mixing bowl, melt butter and combine it with crushed graham cracker crumbs and a sprinkle of sugar. Press into the bottom of a baking dish and bake at 350°F for 8-10 minutes.

In a bowl, beat softened cream cheese with powdered sugar, milk, and vanilla until smooth. Fold in Cool Whip.

Spread the cream cheese mixture over the cooled crust, then add the cooled raspberry filling, swirling gently.

Cover with plastic wrap and refrigerate for at least 6 hours before serving.