In a heatproof bowl, dissolve the strawberry Jello powder in boiling water, stirring until completely dissolved.
Stir in the cold water until well combined. Set the Jello mixture aside to cool to room temperature, but do not let it set.
In a separate mixing bowl, beat the softened cream cheese, granulated sugar, and vanilla extract together until smooth and creamy.
Gradually pour the cooled Jello mixture into the cream cheese mixture, beating continuously until smooth and well combined.
Gently fold in the sliced strawberries until evenly distributed throughout the filling.
Pour the strawberry Jello mixture into the pre-made graham cracker pie crust, spreading it out evenly with a spatula.
Refrigerate the pie for at least 4 hours, or until set and firm.
Once the pie is set, garnish with additional sliced strawberries and a dollop of whipped cream, if desired, before serving.
Slice and serve chilled. Enjoy your delicious no-bake strawberry Jello pie!