Step 1

Preheat oven to 180*C/350°F (160°C fan-forced). Grease and line the base only of a 23cm / 9" tart tin with a loose base. (Or a springform pan of a similar size)

Step 2

Blitz biscuits - Roughly break up biscuits and place in a food processor, then whizz until fine crumbs form. Or do this step with a ziplock bag and rolling pin.

Step 3

Press - Pour crumbs into a bowl, add melted butter, mix until it looks like wet sand and no dry crumbs remain. Pour into tin, then press firmly into base and sides – use something flat like a cup to assist (refer to video).

Step 4

Bake & cool - Transfer to tray (safe handling), place in oven and bake for 10 minutes, then remove and cool slightly (5 minutes in fridge).

Step 5

Melt butter in a large saucepan over medium heat. Add sugar and whisk to combine – butter may not incorporate fully.

Step 6

Whisk - Once it starts bubbling and the sugar is completely melted, pour in the condensed milk, whisking as you go. Whisk constantly until you see steam coming off the caramel (~ 4 minutes), then remove from heat.

Step 7

Pour into base - Add salt (adjust to taste), then pour the caramel into the tart base.

Step 8

Bake for 15 minutes or until the edges of the caramel surface is golden and the surface has a “skin” on it, but the caramel is still soft and the centre jiggles slightly (see video for demo.)

Step 9

Cool on counter while you make the chocolate.

Step 10

Melt chocolate - Place cream and chocolate in a heat proof bowl. Microwave in 2 x 30 second bursts, stirring in between, until smooth.

Step 11

Cool then pour - Set aside for 10 minutes to thicken slightly, then pour over the base. Smooth top or make swirls like I did (just wait until the chocolate thickens slightly). Sprinkle with sea salt flakes.

Step 12

Refrigerate for 1 ½ hours to allow chocolate to set. Then remove and bring to room temperature before slicing to serve. Handle carefully when sliding the tart off the base - or just leave it on to be safe and just remove the sides.