In a bowl, combine graham cracker crumbs, granulated sugar, and melted butter until the mixture resembles wet sand.
Press the mixture into a 9-inch pie dish. Use the back of a spoon or measuring cup to form an even crust.
Refrigerate the crust for 30 minutes or freeze for 15 minutes to set.
In a large bowl, beat softened cream cheese until smooth.
In another bowl, whip heavy whipping cream with powdered sugar and vanilla extract until stiff peaks form.
Fold the whipped cream into the cream cheese mixture until smooth. Fold in fresh raspberries if using.
Spread the filling into the chilled crust and refrigerate while preparing the topping.
In a small saucepan, combine raspberries, granulated sugar, and lemon juice over medium heat. Cook for 5 minutes until the berries break down.
Mix cornstarch with water to make a slurry, then stir into the raspberry mixture. Cook for 1-2 more minutes until thickened. Let cool slightly.
Spread the raspberry topping evenly over the cream filling.
Refrigerate the pie for at least 2 hours until set.
Garnish with fresh raspberries, whipped cream, or mint leaves if desired. Slice and serve chilled.