Preheat the oven to 350°F.

Wrap the outside of a 9-inch springform pan with heavy-duty foil (to prevent water bath leaks).

Mix Biscoff crumbs, melted butter, brown sugar, and salt until evenly moistened.

Press into bottom and 1-inch up the sides of the springform pan using a flat-bottomed measuring cup.

Bake for 8–10 minutes until set and fragrant.

Remove and reduce oven temp to 325°F.

Place a large baking pan (like a roasting pan) in the oven. Fill with about 1 inch of hot water and keep it there while you prepare the filling.

Beat softened cream cheese until completely smooth (no lumps), about 1.5 minutes. Scrape bowl.

Add sugar and lemon zest, beat 1 minute more.

Add eggs one at a time, mixing and scraping between additions.

Add lemon juice, vanilla, sour cream, flour, and whipping cream. Mix until just combined.

Stir in melted white chocolate by hand, just until fully incorporated.

Pour filling into the cooled crust. Gently shake to level.

Place the springform pan into the water bath in the oven.

Bake 85–95 minutes until edges are puffed but center still slightly jiggles.

Turn the oven off, crack the door, and let cheesecake cool in the oven for 1 hour.

Remove and cool completely on a wire rack for 1.5–2 hours. Do not rush this by chilling.

Cover and refrigerate overnight.

Whip 1 cup heavy cream to soft peaks.

Gently fold in 1/2 cup lemon curd until smooth.

Spread over fully chilled cheesecake.

Whip cream with powdered sugar, vanilla, and cornstarch to stiff peaks.

Pipe or dollop along the edges.