Preheat oven to 325°F (163°C). Wrap the bottom of a 9-inch springform pan with heavy-duty foil and grease sides. In a medium bowl, combine graham cracker crumbs, granulated sugar, and melted butter. Press mixture firmly into the bottom and up the sides of the prepared pan. Bake 10 minutes until golden around the edges. Cool on a wire rack.

In a stand mixer fitted with the paddle attachment, beat cream cheese and sugar on medium speed until smooth. Add sour cream, flour, and vanilla extract; mix until combined. On low speed, add eggs and yolks one at a time, mixing until just blended. Pour in heavy cream and gently stir until the batter is silky and ribbon-like.

Place the springform pan in a large roasting pan. Pour the filling over the cooled crust. Carefully pour hot water into the roasting pan until it reaches halfway up the sides of the springform. Bake for 70 minutes, or until the center jiggles slightly when nudged.

Turn off the oven and crack the door open. Let the cheesecake rest inside for 60 minutes to finish setting without an abrupt temperature change.

Remove the pan, cool completely on a rack, then refrigerate for at least 4 hours or overnight before adding the caramelized topping.

Just before serving, sprinkle granulated sugar evenly over the chilled cheesecake. Use a culinary torch to caramelize the sugar, waving the flame about 4 inches away until it bubbles and turns amber. Allow sugar to set for a minute before slicing.