Preheat oven to 350°F. Mix gingersnap crumbs, 1/4 cup sugar, and melted butter. Press into a 9-inch springform pan. Bake 10 minutes, then cool.

Lower oven to 325°F. Beat cream cheese and 1 cup sugar until smooth, about 3 minutes. Mix in vanilla. Add eggs one at a time on low, then fold in sour cream.

Whisk pumpkin, brown sugar, spices, and flour until smooth. Pour half the plain batter into the crust, dollop half the pumpkin mixture, then repeat with remaining batters. Swirl with a knife in a figure-eight pattern.

Set pan in a roasting pan, fill with hot water halfway up the sides. Bake 60 to 70 minutes until edges are set and center jiggles slightly. Turn off oven, crack door, and leave inside 1 hour. Cool completely at room temperature, then refrigerate at least 6 hours or overnight.

Run a knife around the edge, remove ring. Slide onto a serving plate if desired.

Slice with a hot, dry knife, wiping between cuts. Serve cold or let stand 20 minutes at room temperature.