Step 1

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

Step 2

Line inverted base: Get a 20cm/8" springform cake tin. Turn the base UPSIDE DOWN (Note 4), butter lightly then press on a square piece of parchment/baking paper. Then clip into the springform pan - excess paper will stick out, see photos in post and video.

Step 3

Line sides: Butter and line the side of the pan.

Step 4

Break up biscuits roughly by hand and place in a food processor.

Step 5

Blitz until fine crumbs. Add butter, briefly blitz until dispersed and it resembles wet sand.(Note 5)

Step 6

Pour into the prepared cake tin. Use a spatula to roughly spread it out over the base and up the walls.

Step 7

Use something with a flat base and vertical edges (I use a measuring cup) to press the crumbs up the wall almost to the top of the sides, and flatten the base.

Step 8

Cream cheese: Use a stand mixer (with paddle) or handheld beater to beat the cream cheese until just smooth, no longer than 20 seconds on speed (You do not want to aerate cheesecake filling too much as it causes cracks when it bakes)

Step 9

Add flour, beat for 5 seconds on speed 4 until just incorporated.

Step 10

Add vanilla, sour cream, sugar and lemon zest. Beat until just combined (10 sec max, speed 4).

Step 11

Eggs: Add eggs one at a time - beat for 5 seconds on speed 4 in between each. After the last egg, beat as needed until batter is smooth - but stop beating immediately once smooth.

Step 12

Blueberries: Stir in blueberries with a rubber spatula. Pour into prepared crust.

Step 13

Bake: Bake for 70 minutes. The top should be a bit puffed, very light golden brown, not cracked, and near perfectly flat. It should jiggle slightly when you gently shake the pan, see video at 1 min 23 sec (sets in next step).

Step 14

Cool: Cool the cake in the oven with the door open approx 20 cm / 8" for about 2 hours (Note 6), then refrigerate for 4 hours+ in the pan or overnight. Cake will sink and surface should be flat.

Step 15

Release: Remove sides of springform pan. Use overhang paper to slide cheesecake off the cake pan base. Then slide the cheesecake off the paper.

Step 16

Place 1 cup of blueberries (125g/4oz), vanilla, sugar and lemon juice in a saucepan. Stir then bring to simmer over medium heat. Simmer for 7 minutes until blueberries breakdown.

Step 17

Mix cornflour and water, then stir in - it wil thicken quickly.

Step 18

Stir in remainig blueberries. Sauce should be syrupy - remove from stove and cool. Will thicken as it cools.

Step 19

Once cool, stir. Adjust thickness 1/2 teaspoon of water at a time to make it the perfect "oozing" consistency (see video, Note - be careful, don't make it runny!

Step 20

Spoon onto cheesecake so it's completely covered - you'll have maybe 1/2 cup sauce left, good for touch ups. Refrigerate 2 hours+.

Step 21

Slice and serve!