Combine cream cheese and granulated sugar in a bowl, and mix it over a hot-water bath until it has a smooth texture.
Combine sour cream and Greek yogurt in another bowl, and mix well using a rubber spatula.
Add the 2 egg yolks into (2) in thirds, mixing well with a whisk after each third is added. Add lemon juice and corn starch and mix well.
Heat the heavy cream in a small pan on medium heat, then add white chocolate, grated tonka beans, and vanilla bean seeds and pods. Turn off the heat after brought to a boil.
Mix (1) and (4) with a whisk. Add (3) and mix until it becomes smooth. Strain the mixture and pour into a cake tin lined with parchment paper.
Place the filled cake tin on an oven pan and place into the oven. Pour 3 cm of water into the oven pan.
Bake at 180℃ for 25 min. and 150℃ for 20 min. Take out of the oven, allow it to cool, and take the cheesecake out. Cool in the refrigerator for at least 4 hours.
