1-2 tablespoons turbinado sugar (sugar in the raw)
Preheat the oven to 375º.
Mix the graham cracker crumbs, sugar and melted butter till well combined. Pat half onto the bottom and about half way up the sides of each of two 5 x 2 1/2 inch round spring form pans. Or use whatever smaller spring form pans you have which could hold 5 cups of batter. Bake for 5-7 minutes till crust slightly darkens. Remove to rack and cool. Reduce oven temperature to 300º.
Using the paddle attachment of your stand mixer, beat cream cheese, mascarpone, flour and salt till smooth and fluffy, about 5 minutes. Add sugar and continue mixing till smooth then add and mix in vanilla paste. Add eggs one at at time, mixing just until incorporated. Divide batter between the 2 spring form pans.
Bake for about 40 minutes or till most of cheesecake is set and only the middle is slightly jiggly when pan is tapped. Remove to rack and cool completely. Place in refrigerator and chill at least 8 hours. Carefully remove sides of spring form pans, then use an spatula to release cheesecakes from bottom of the pans onto serving plates.
To serve, sprinkle each with a scant 1 tablespoon of turbinado sugar and use kitchen torch to melt the sugar.