Separate 6 eggs into yolks and whites, and let them come to room temperature. Adjust oven rack to the lower-third position, and preheat your oven to 320 F (160 C), and begin boiling a large pot of water for the water bath.

Prepare a double-boiler set up. I use a metal bowl over a saucepan with simmering water over low heat. Add in 8 oz of cream cheese, 4 tbsp of unsalted butter, 3/4 cup of heavy cream, and 5 tbsp of granulated sugar. Let the ingredients melt together while whisking to combine.

Once the mixture is warm and well-combined, remove the bowl from the heat. Add in 1 tbsp of ube extract, 1/4 tsp of salt, and whisk them in. One at a time, add in the 6 room temperature egg yolks from earlier, making sure the previous yolk is combined before adding the next one.

With a sieve, sift 2/3 cup of cake flour into the batter. Continue to whisk till the dry ingredients are mixed in.

Into another large (clean) mixing bowl, strain the batter through the sieve to remove any lumps. Set this batter aside for now.

In the bowl of your stand-mixer, add in the 6 room temperature egg whites and 1/2 tsp of cream of tartar. With the whisk attachment, beat the egg whites on medium speed till they become foamy. When they look foamy, increase the speed to medium-high, and slowly add in 1/2 of granulated sugar. When all the sugar has been added, continue beating till the egg whites stiff peaks form.

One-third at a time, gently fold the egg-white meringue into the ube batter, until everything is well incorporated and the mixture looks smooth.

Take a 9" springform pan that has a height of at least 3", and pour the batter into the springform pan. Tap the springform pan against the counter to release any big air bubbles and let the batter spread evenly.

Place 2 large sheets of aluminum foil over a large roasting tray. I use an 11" x 15" roasting tray that's 2" high. You can use any size, as long as the springform pan fits inside it. Place the springform pan in the center of the foil, and fold up the foil so that it creates a high 2-layer wall of foil that is hugging the sides of the springform pan, and overshooting a bit in terms of height - about 1 inch or so higher than walls of springform pan. It's important that there are no holes or tears in the foil so water will not leak into the cheesecake. The 2 layers of foil will help to ensure this.

With the 9" springform pan in the center of the larger roasting tray and the wall of aluminum foil in place, place the roasting dish on the lower third rack in your preheated oven, with the roasting dish not pushed all the way in. Do not close the oven door yet. When the roasting dish is in the oven, pour boiling water into the roasting dish so that it goes up about one inch high, creating a water bath for the cheesecake. The springform pan with the cheesecake should be heavy enough to weigh it down, and it will not float in the water. Very carefully (so water doesn't slosh around) push the roasting dish further into the oven so it is centered, and close the oven door.

(Pouring the boiling water while the roasting dish is already in the oven will avoid having to carry the heavy dish with boiling water inside it).

Bake at 320 F (160 C) for 45 minutes. Then turn down the temperature to 285 F (140 C), and continue baking for another 45 minutes.

Leaving the oven door closed, turn off the heat, and let it rest in the cooling oven for another 2 hours.

After resting in the turned-off oven / water bath for 2 hours, remove the water bath from the oven, and carefully lift the cheesecake out of the water bath. Be very careful as water could still leak into the cheesecake at this point.

Let the cheesecake finish cooling to room temperature, uncovered, on a metal rack. This will take another 1 hour or so.

By the time it has reached room temperature, the cake will have shrunk a little bit and will have already detached from the sides of the pan. Remove the sides of the springform pan and leave the bottom part under the cake.

Slice and serve at room temperature. Refrigerate leftovers. After chilling, let it stand for 20 to 30 minutes at room temperature before serving to let it come back to a nice fluffy consistency again.


Coconut Whipped Cream:

While waiting for the cheesecake to cool, take the bowl of the stand-mixer, add in 2 cups of very cold heavy cream and 1/2 a cup of cold coconut cream (separated from 13.5 oz can of full-fat coconut milk). With the whisk attachment, beat on medium-high speed till the heavy cream mixture increases in volume, about 50% increase in volume.

Then while continuing to beat, add in 1/4 cup of granulated sugar and 1 tsp of vanilla extract. Continue beating on medium-high speed until the mixture forms stiff peaks. Leave this whipped cream in the fridge till you're ready to serve.

Serving:

Sift powdered sugar over the top of the cake just before serving. Serve the Japanese / Soufflé-style ube cheesecake with a dollop of coconut whipped cream. Enjoy!