In the bowl of a stand mixer fitted with the paddle attachment, or in a large bowl with an electric mixer, beat the cream cheese for 3 minutes. Scrape down the sides of the bowl and add in powdered sugar and vanilla and beat an additional 3 minutes.
Fold in whipped topping until completely incorporated.
Fold in the strawberries and marshmallows.
Cover and refrigerate for at least 2 hours.
If desired, top with additional whipped topping and crushed graham crackers just before serving.