Mix cream cheese, white sugar, and vanilla extract in a large bowl until smooth. Stir 3/4 cup mashed strawberries into cream cheese mixture.
Beat heavy cream and confectioners' sugar in a glass or metal bowl until stiff peaks form. Lift your beater or whisk straight up: the cream will form sharp peaks. Fold whipped cream into cream cheese mixture until evenly mixed; fold in remaining 1/4 cup sliced strawberries.
Spoon strawberry mixture into graham cracker crust. Chill at least 3 hours before serving.