While the tea biscuit crust is baking, make the pineapple reduction. In a small saucepan, simmer the pineapple juice on medium low heat until it's reduced to 1/3 of a cup. Approximately 12-15 minutes. It will be thicker and darker in color. Don't boil it. Set it aside to cool.
While the crust is cooling, boil 8 cups of water for the water bath (bain-marie). I like to do this in a tea kettle so it’s easy to pour the water into the roasting pan. Keep it warm until we are ready to pour it in the roasting pan for the water bath.
While the crust is cooling, in a stand mixer with paddle attachment (or a hand-mixer), beat the cream cheese to break it up for 10 seconds. On low speed, slowly add the sugar then increase to medium and beat until well combined, smooth and creamy, about 2-3 minutes.
Scrape the bowl down with a silicone spatula. Add the sour cream, pineapple reduction, lemon juice, vanilla and salt and beat on medium speed until just combined. Scrape the bottom of the bowl down again.
On medium speed, add the eggs one at a time until just blended in. Don't overmix. After the eggs are completely blended, scrape the bowl down once more.
Pour the cheesecake filling into the cooled springform pan with the foil wrapped around it.
Put the springform pan into a large roasting pan and place the roasting pan into the oven. Carefully, pour boiling water into the roasting pan, taking care to not splash water into the cake. Fill the roasting pan so the water comes halfway up the outside of the springform pan. Please be careful to not burn yourself.
Bake the cheesecake for 55-70 minutes. When the cheesecake is done, it will tighten at the edges and the center will have a slight jiggle when you shake the pan. The temperature of the cake should be 150-155 degrees F/ 65.5 – 68.3 degrees C.
When the cheesecake is done, turn off the oven and slightly prop open the oven door. Leave the cake in the cooling oven for an hour in order to gradually cool the cheesecake. This prevents the cake from cracking and keeping the top smooth and even.
After an hour, take the cheesecake out of the water bath and remove the aluminum foil from the outside of the springform pan. Set it on a cooling rack on the counter and let it cool down to room temperature, approximately 2 hours more.
When the cheesecake is completely cooled, keep the cake in the springform pan. Top with the pineapple curd on the cheesecake. Spread it in an even layer all over the top with an offset spatula or a silicone spatula.
Cover the springform pan tightly and refrigerate the cake for at least 4 hours or overnight.
Carefully release the springform pan rim. Cut the cheesecake into wedges and serve.