Line a 9x5 inch loaf tin with non-stick baking paper, leaving an overhang for easy removal. Set aside.
In a blender, blitz the biscuits until finely crumbed and sandy. Transfer to a mixing bowl and stir in the butter. The mixture should clump together when pressed between your fingers and the crumbs should all be moistened. I needed about 1 and a half tablespoons of butter, you may need more depending on the biscuits. Press this mixture into the base of the prepared tin, pressing it down firmly and evenly. Place the tin in the fridge for 20 minutes.
Preheat the oven to 160 C.
To make the filling, combine the cream cheese, yoghurt and cream in a bowl. Beat with a hand mixer on low speed for about 20 seconds, until smooth and creamy.
Add the lemon zest, vanilla and sugar and beat again to combine. The sugar will loosen up the mixture considerably. Do not over-beat, or your cheesecake might crack.
Finally, sprinkle the cornflour into the bowl and beat for just a few seconds to incorporate it, or stir using a spatula. At this stage, you can add a couple more tablespoons of sugar if the batter tastes under-sweetened. The batter is pourable but not super runny. Pour over the chilled biscuit base and smoothen the top.
Bake the cheesecake for about 1 hour, until the top has browned (not too dark) and the sides look set but the surface still has a wobble to it. Usually, only the center should wobble but in this loaf form with an eggless filling, the wobbly area is much larger. Start checking for doneness at 45 minutes since ovens vary and cheesecakes tend to be a bit finicky.
Once the top looks browned, let the cheesecake cool in the oven itself for about 15 minutes. Then take it out and let it cool at room temperature where it will fall slightly and begin to firm up and set on its own. If you gently shake the tin, you will see that the surface is no longer wobbly. The inside will be perfectly creamy when you cut it. Over-baking till it's completely firm will lead to a dense, solid texture which we don't want.
Chill the cheesecake overnight and the next day, use the paper overhang to lift it out and slice into squares or triangles. (You might find raised edges of the cheesecake sticking to the sides of the paper, you can just trim those off.) Store in the fridge in an airtight tin for 4 to 5 days and in the freezer for a month. Happy baking!