Prepare the pan: Lightly grease the bottom and sides of a 9-inch springform pan or line the base with parchment for easy removal.
Make the crust: In a bowl, stir together the cookie crumbs, melted butter, sugar (if using), and a small pinch of salt until the mixture resembles wet sand. It should clump when pressed.
Press and chill: Pour the crumb mixture into the pan and press firmly into an even layer, going slightly up the sides. Use the bottom of a measuring cup to pack it tight.
Chill in the fridge for at least 20 minutes.
Beat the cream cheese: In a large bowl, beat the softened cream cheese and 3/4 cup powdered sugar on medium speed until smooth and fluffy, about 2–3 minutes. Scrape the bowl well.
Flavor the base: Beat in the vanilla and 1/2 cup salted caramel sauce until evenly combined. Taste and adjust sweetness if needed.
Whip the cream: In a separate bowl, whip the cold heavy cream with 1/4 cup powdered sugar until medium-stiff peaks form.
Don’t overbeat—stop when the cream holds its shape.
Fold it together: Gently fold the whipped cream into the cream cheese mixture in two additions, using a spatula. Keep it airy by folding, not stirring.
Season with salt: Add fine sea salt to taste, starting with 1/4 teaspoon and adding more if you like a stronger salted caramel profile. The salt should brighten the caramel, not dominate it.
Fill the crust: Spoon the filling into the chilled crust and smooth the top.
Tap the pan lightly on the counter to release air pockets.
Chill to set: Cover and refrigerate for at least 6 hours, preferably overnight. The longer it chills, the cleaner the slices.
Finish and serve: Just before serving, loosen the pan’s sides with a thin knife and release the springform. Drizzle with extra caramel and sprinkle with flaky sea salt.
Add whipped cream and toffee or nuts if you like crunch.