Add the cream cheese, powdered sugar, vanilla, and pumpkin pie spice (if using) to the bowl of a stand mixer fitted with the paddle attachment. Mix on low until combined, then increase speed to medium-high and beat until smooth & creamy, about 1 minute. Transfer mixture to a small bowl; set aside.
In the bowl of a stand mixer fitted with the whisk attachment, add the chilled cream and beat until stiff speaks form. Add the cream cheese mixture and mix on low until just combined.