Preheat oven to 325 degrees F. Grease a 9-inch springform pan.

Mix graham cracker crumbs, sugar, and melted butter. Press firmly into the bottom of the pan. Bake 8-10 minutes, then set aside to cool.

Beat cream cheese until completely smooth, scraping the bowl often. Add sugar and flour, mix until combined. Mix in sour cream, heavy cream, and vanilla. Add eggs and the extra yolk one at a time, mixing on low just until each is incorporated. Do not overbeat once the eggs are in.

Wrap the outside of the springform pan tightly in foil and set it in a larger roasting pan. Pour in the filling, then place the roasting pan in the oven and pour hot water into it until it comes about 1 inch up the side of the springform pan. Bake at 300 degrees F for 75-90 minutes, until the edges are set but the center still jiggles slightly.

Turn off the oven, crack the door, and let the cheesecake sit in the cooling oven for 1 hour. Remove it, run a knife around the edge, and chill in the fridge uncovered at least 8 hours, ideally overnight.

Melt butter, brown sugar, heavy cream, corn syrup, and salt in a saucepan over medium heat. Simmer 3-4 minutes until slightly thickened, stirring often. Remove from heat and stir in pecans and vanilla. Let cool 10-15 minutes, until warm but not hot, before pouring over the chilled cheesecake.

Chill another 30 minutes to let the topping set before slicing.