Caramel - melt sugar in 4 batches, whisk in salt,butter and cream off heat, simmer 1 min. Fully cool. Base - blitz biscuits into crumbs, then everything else. Press into lined 23 x 33cm pan (9x13"). Filling - Beat cream cheese, then beat in vanilla, sour cream, sugar and salt. Beat in eggs one at a time. Pour over base, swirl in half the caramel, bake 35 min @ 160°C/320°F (140°C fan), cool in door-open oven, fridge 6 hrs. Drizzle with caramel and salt flakes.

Melt sugar in 4 batches - Spread 1/4 of the sugar in a medium saucepan over medium high heat (or medium, if it's a strong stove). Let it melt, stirring if needed, then add another 1/4 of the sugar, melt, then repeat twice more.

Amber colour - Once all the sugar has melted, leave it on the stove for 1 - 2 minutes until it becomes an amber colour. ⚠️DON'T WALK AWAY! Sugar burns easily.:)

Make it caramel! Remove the saucepan off the stove. Add the salt and butter, whisk until melted (it may not combine with the sugar, that's ok). Then slowly and carefully pour in ~1/3 of the cream (⚠️ it will steam and bubble a bit). Whisk that to combine, then whisk in remaining cream (it won't bubble).

Simmer - Return to the stove, still on medium high. Once you see bubbles, let it simmer for 1 minute, stirring and scraping down sides as needed.

Cool 1 hour - Pour into a bowl. Cover with cling wrap touching the surface (to prevent a skin from forming). Let it fully cool on the counter before using - about 1 hour.

Preheat oven to 160°C/320°F (140°C fan-forced). Place shelf in middle of oven.

Line pan: Lightly grease a 23 x 33cm / 9 x 13" metal pan with unsalted butter. Line with baking paper with overhang to lift the cheesecake out at the end.

Blitz - Break up biscuits roughly by hand and place in a food processor. Blitz until fine crumbs. Add cinnamon, sugar, salt and butter. Briefly blitz until it resembles wet sand. (Note 6)

Pour into the prepared pan, then firmly press it evenly across the base (base only, not the sides).

Cream cheese: Use an electric beater or stand mixer fitted with the paddle (not whisk). Beat the cream cheese just until smooth, no longer than 20 seconds on speed 4. (You want to minimise air bubbles in the batter as they are unsightly).

Add vanilla, sour cream, sugar and salt. Beat until just combined.

Add eggs one at a time, beating in between for just 5 seconds. After the last egg, beat as needed until batter is smooth - but stop beating immediately once smooth.

Pour the mixture onto the base and spread out evenly.

Caramel swirls - Use a spoon to randomly dollop half the salted caramel you made across the surface. Then use a chopstick to make some swirls. Not too many - we don't want to mix the caramel into the batter, you just want to spread it across the surface. Don't worry about prettiness (we drizzle more on at the end).

Bake for 35 minutes. The middle should still be a bit soft, but not like a waterbed (ie runny batter under surface skin).

Cool in oven - Cool the cheesecake in the oven with the door open approx 20 cm / 8" for about 1 hour (Note 6)

Fill cracks and decorate - As it cools, some of the swirls will open up into cracks. Use a teaspoon to fill these with salted caramel, then use most of the remaining caramel to do bold drizzles across all across the surface, I use about 3/4 of it (use leftover for serving, or another use).

Fridge set - Refrigerate the cheesecake in the pan for 6 hours+ or overnight.

Remove & cut - To remove, lift the cheesecake out using the paper overhang. Sprinkle with salt flakes. Cut into however many pieces you desire - 16 bars (pictured), or into 40 x 4cm or 77 x 3cm Petit Four size squares (adorable!).