Place the cream cheese in a large microwave-safe bowl and microwave for about 10 seconds to soften. Add in the brown sugar, vanilla extract, and cinnamon. Whisk or stir with a rubber spatula until the mixture is smooth and creamy—similar to frosting—about 1 minute.
Slowly pour in the heavy cream and whole milk, stirring until everything is fully combined and the sugar has dissolved.
Transfer the mixture into a Ninja Creami pint container. Seal it with the lid and freeze for 24 hours, or until completely solid.
After freezing, remove the pint from the freezer and take off the lid. Place the pint into the outer bowl, attach the paddle to the lid, and lock it into place. Set the bowl assembly onto the motor base and twist the handle to raise and secure the platform.
Select the “ICE CREAM” setting and let the machine do its magic.
Once blended, use a spoon to create a 1½-inch hole in the center of the pint, reaching all the way to the bottom. Fill the hole with chopped frozen Pop-Tarts pieces. Run the “MIX-IN” cycle to blend them into the ice cream.
Scoop and serve immediately, topping with extra Pop-Tarts pieces if desired. Enjoy this nostalgic, creamy treat!