Preheat oven to 350 degrees Fahrenheit. Butter a 10-inch springform pan and line the bottom with a circle of parchment paper.

In the bowl of an electric mixer fitted with the paddle attachment, beat the cream cheese on medium speed until fluffy, about 3 minutes, scraping down sides as needed. In a large bowl, whisk together remaining 2 1/4 cups sugar and flour. With mixer on low speed, gradually add sugar mixture to cream cheese; mix until smooth.

Add sour cream, truffle oil and vanilla. Mix until smooth. Add eggs, one at a time, beating until just combined. Do not over mix.

Pour cream cheese filling into prepared pan. Set pan inside a large, shallow roasting pan. Carefully ladle boiling water into roasting pan to reach halfway up sides of springform pan.

Bake 45 minutes; reduce oven temperature to 325 degrees. Continue baking until cake is set but still slightly wobbly in the center, about 30 minutes more. Turn off oven; leave cake in oven with door slightly ajar, 1 hour.

Transfer pan to a wire rack; let cake cool completely. Refrigerate, uncovered, at least 6 hours or overnight. Before unmolding, run a knife around the edge of the cake.