In a mixing bowl, cream together the butter, powdered sugar, and vanilla until light and fluffy. Incorporate the egg yolk, then gradually add flour and milk until a firm dough forms. Press into the bottom of a greased baking pan.

Preheat oven to 350°F (175°C). Bake the crust for 15 minutes or until lightly golden. Let it cool completely on a wire rack.

In a saucepan, combine water and cornstarch over medium heat until it boils. Stir in sugar, Raspberry Jell-O, and fresh raspberries. Cook on low heat until thickened (about 5-7 minutes), then let cool slightly.

In a bowl, beat cream cheese with powdered sugar and vanilla until smooth. In another bowl, whip heavy cream until stiff peaks form, then gently fold into the cream cheese mixture.

Spread the cream cheese mixture over the cooled crust, then pour the raspberry mixture on top, spreading evenly. Refrigerate for at least 1 hour to set.

Cut into squares with a sharp knife, wiping the blade between cuts for clean edges. Garnish with fresh raspberries or powdered sugar if desired.