Portion the crumbs: Spoon the crumb mixture evenly into the bottom of each jar, about 2 to 3 tablespoons per jar depending on size. Lightly press the crumbs down with the back of a spoon or your fingers to form a loose base. Do not pack too firmly; you want them to stay tender and easy to scoop.
Beat the cream cheese and sugar: In a medium mixing bowl, add the softened cream cheese, 1/3 cup granulated sugar, vanilla extract, and a pinch of salt if using. With a hand mixer (or a sturdy whisk and some elbow grease), beat until completely smooth, creamy, and no lumps remain, scraping down the sides of the bowl as needed.
Add the cream: Pour the cold heavy cream into the cream cheese mixture. Beat on medium-high speed until the mixture thickens and becomes light and fluffy, 1 to 2 minutes. You are looking for a texture similar to soft whipped cream that holds gentle peaks but is still spoonable. You may see soft pieces of cream cheese throughout; that’s fine and gives a homemade texture.
Fill the jars: Spoon the cheesecake mixture over the crumb bases, dividing it evenly among the jars. Fill almost to the top. To create a swirled top, use the back of a spoon to gently twist and lift the surface, making loose, circular swoops.
Chill briefly: Place the filled jars on a tray and refrigerate for at least 30 minutes, or while you get the rest of your snacks or coffee ready. They will firm up a bit but remain soft and creamy—more like a mousse than a baked cheesecake.
Serve: Just before serving, you can leave the tops plain to show off the swirls or add a tiny spoonful of jam or a few fresh berries if you like. Serve the cheesecake cups directly from the jars with small spoons. Store any leftovers covered in the refrigerator for up to 2 days.
For a fruit-topped version, add a spoonful of store-bought fruit preserves or pie filling (cherry, blueberry, or strawberry) on top of each chilled cup just before serving. For a chocolate twist, stir 2 tablespoons of cocoa powder and an extra tablespoon of sugar into the cream cheese mixture, and sprinkle a few chocolate chips over the crumb layer before adding the filling. To lean into a more tangy profile, replace 2 to 3 tablespoons of the heavy cream with sour cream or plain Greek yogurt; this gives a flavor closer to traditional New York–style cheesecake. If you prefer a firmer texture, refrigerate the cups for 2 to 3 hours instead of 30 minutes. For a nutty variation, swap in half finely ground toasted nuts (like pecans or almonds) for part of the graham cracker crumbs in the base. You can also play with flavor extracts—almond, lemon, or even a splash of bourbon—keeping the total to about 1 teaspoon so the cream cheese remains the star.