If making graham cracker crumbs from whole crackers: Place graham crackers into a food processor and process until finely ground. Or place crackers in a large plastic bag and use a rolling pin to finely crush.
If using a food processor: Add melted butter, sugar, and salt (optional) to food processor with graham cracker crumbs and pulse until fully incorporated. Or, add crumbs, butter, sugar, and salt to a bowl and mix until evenly combined. Your mixture should be thick and sandy.
Line a 9x13 baking pan with parchment paper. Pour graham cracker mixture into prepared pan. Use the flat bottom of a measuring cup and/or your hands to press crust firmly into the bottom of the pan. Transfer to refrigerator while preparing filling.
In a large mixing bowl, add cream cheese. With a hand mixer, blend unto smooth and creamy, about a minute. Add confectioner's sugar, sour cream, and vanilla extract. Beat until smooth and creamy, about a minute.
In a separate large bowl, add cold heavy cream. Using a hand mixer with a whisk attachment, whip for 2-3 minutes on medium speed until stiff peaks form. Once you begin to see ripples in the cream from your mixer and it appears to be holding its shape, stop the mixer and pull the whisk out of the bowl. If the tip of the whipped cream holds its shape without drooping, your whipped cream is ready. Take care not to over-mix or your whipped cream will separate.
Using a spatula, gently fold whipped cream into cream cheese mixture until fully incorporated. Pour cheesecake filling over prepared graham cracker crust and using a spatula, spread to the edges of the pan in an even layer.
Cover and refrigerate 8 to 12 hours, or overnight, until firm. Keep refrigerated until ready to serve. Slice and serve cold.
1.5 cups of heavy cream can be substituted with an 8 ounce tub of Cool Whip. Skip the step of whipping your cream, then fold Cool Whip into cream cheese mixture as directed.
No-bake cheesecake will keep for 5 days in the refrigerator in a sealed container, and is best after resting for at least 8 hours. A great dessert to make a day or two ahead of an event.
For tips on making a sturdy graham cracker crust and preventing a runny filling, please see tips in the post above.