• Preheat oven to 140c (fan forced).

To line the tin

• Take a 20cm (8") spring form pan, remove the base and flip it upside down then grease the base with butter.
• Place a square of baking paper on top of the base (there will be some overhanging the sides), clip the outer ring back on over the top of the baking paper, then grease and line the sides.

Base

• In a bowl combine butter and biscuit crumbs, mixing to incorporate.
  250 g plain sweet biscuits (I used Arnott's Marie), 140 g salted butter
• Press the crumb mixture firmly into the base and up the sides of the tin using a glass (or something with a flat base and sides) to compact. The mixture should come roughly to the top of the tin.
• Place in the fridge to firm up while you continue with the filling.

Filling

• In a large bowl combine cream cheese, flour and salt. Using a handheld or stand mixer, mix until just combined.
  500 g cream cheese, 2 tablespoons plain (all-purpose) flour, ¼ teaspoon salt
• Add sour cream, sugar and vanilla, mixing again until just smooth.
  270 g caster sugar, 125 g sour cream, 1 tablespoon vanilla extract
• Incorporate eggs one at a time, mixing with each addition.
  3 eggs
• Pour cheesecake batter into the base, give it a few gentle taps on the counter and pop any air bubbles that rise to the surface.
• Bake for 55 minutes or until it's lightly browned and the centre is set but still has a slight wobble when you shake the pan.
• Turn the oven off, then leave the oven door ajar 10 to 20 cm to allow the cheesecake to slowly cool in the oven.
• Once cool, place in the fridge (in the tin) for 4 hours to set.

Lemon curd layer

• Whisk the lemon curd so that it's smooth, then spoon it on top of the cheesecake using a small spatula to spread it into an even layer.
  ¾ cup lemon curd
• Slice and serve.