Lower the oven temperature to 325F.
Using a handheld electric mixer or a stand mixer fitted with the paddle attachment, beat cream cheese on medium speed until fluffy (2-3 mins).
Add sugar and continue beating for another 2 minutes.
Add ube jam and sour cream. Beat until smooth and well incorporated. Make sure to break apart any chunks of ube jam before adding to the mixture.
Add vanilla extract and ube extract and stir until combined. Taste your batter and decide if the cream cheese filling is sweet enough. Add sugar 1 tsp at a time, if necessary.
Add eggs one at a time, beating each one just until combined on a medium-low setting. Scrape the bottom and sides of your bowl to make sure you’re getting to every last inch of batter.
Pour the batter into your pan and tap gently on your counter. Place the pan on your oven's middle rack. Place a roasting pan filled with hot water on the bottom rack.
Bake for 30 minutes at 325F then lower the oven temperature to 300F and bake for 30 minutes more or until set.
Turn the oven off, open the oven door slightly but keep the cheesecake inside for another 1 ½ hour so it can gradually cool.
Take the cheesecake out of the oven, using a knife to run around the edges to separate the cake from the pan. Don't take the cake out of the pan though. Place the cheesecake directly into the fridge to chill for 6-8 hours, preferably overnight.