• Preheat the oven to 180 degrees Celsius/ 360 degrees Fahrenheit.
• If you use a springform with a detachable bottom (with a diameter of about 24-26 cm/9-10 inches) wrap the bottom and the edges of the tin with two layers of aluminum foil (see pictures above in the blog post).
• Grease the bottom of the springform or cake tin and line it with parchment paper cut to fit the bottom of the form.

Base:

• Place the cookies in a food processor and pulse to fine crumbs. Alternatively, place the biscuits in a freezer bag, close well, and crush them using a rolling pin.
• Melt the butter in a small pot and mix with the biscuits. Press this mixture onto the bottom of the prepared tin.
• Bake the base of the lemon curd cheesecake for 10 minutes.

Filling:

• Puree the blueberries and the sugar using an immersion blender or the food processor and set aside.
• Mix the cream cheese, condensed milk, lemon curd, eggs, sugar, lemon juice, and cornstarch until light and fluffy. Pour the filling into the form.
• Add dollops of the pureed blueberries on top and marble the cake using a fork or a knife.

Bake:

• Take a roasting pan or a deeper baking tray that is also wide enough to fit the springform or the cake tin with the cheesecake. Boil water in the kettle.
• Place the springform or the cake tin into this roasting tin or baking tray. I prefer to first place this combination onto the wire rack in the oven and only then fill in the water. Otherwise, the assembly could be too heavy for you to properly lift and place in the oven.
• Very carefully fill the roasting tin or baking tray with enough water to come almost about halfway up the sides of the springform. Be careful not to burn yourself with the hot water or to accidentally flood the cheesecake with water.
• While the blueberry cheesecake is baking, keep checking that the blueberry layer on top doesn't get too dark. If it does, cover the top loosely with aluminum foil.

Baking times:

• If using a regular cake tin, bake the cake for about 50-60 minutes. Check by inserting a toothpick in the middle of the cake. It should come out moist but without cheese hanging on it.
• If using a springform that has been wrapped in a double layer of aluminum foil, bake the lemon curd cheesecake for about 1 hour and 20 or 30 minutes.
• Turn off the heat, leave the oven door wide open for a couple of seconds to allow some of the heat to come out, close the oven again and let the cheesecake in the turned-off oven for another 30 minutes.
• Take out of the oven and let cool completely in the form. I find it tastes even better if you cut it the next day after baking. If left overnight, cover the top and place it in the fridge.