Prepare the crust: Preheat oven to 325°F (163°C). Mix graham cracker crumbs, sugar, and melted butter. Press into a 9-inch springform pan. Bake for 10 minutes, then cool.
Make the raspberry swirl: Cook raspberries, sugar, and lemon juice over medium heat for 5 minutes. Strain to remove seeds. Cool.
Mix the filling: Beat cream cheese and sugar until smooth. Add eggs one at a time, then mix in sour cream, lemon juice, zest, vanilla, and flour.
Assemble: Pour filling over crust. Drop raspberry puree by spoonfuls and swirl with a toothpick.
Bake: Place pan in a water bath. Bake for 55-65 minutes. Cool in oven with door cracked for 1 hour.
Chill and serve: Refrigerate for 4 hours or overnight. Serve with toppings.