Preheat oven to 325 degrees.
Combine the ground wafers and melted butter in a mixing bowl and mix well. Press the mixture on the bottom of a 10-inch springform pan. In a food processor fitted with a metal blade, puree the cream cheese until smooth. Add 2 cups of sugar and process until blended. With the machine running, add the eggs, one at a time. Add the cream, flour, salt and 1 teaspoon vanilla, and mix well. Using a rubber spatula, scrape down the sides of the processor. Process until the batter is smooth. Pour the batter over the crust. Bake for 1 hour and 15 minutes or until the center is firm. Remove from the oven and run a knife around the sides of the pan. Cool on a wire rack. Serve either at room temperature or chilled. In a heavy-bottomed saucepan, combine the remaining sugar, brown sugar, corn syrup, butter, pinch of salt, and condensed milk. With a wooden spoon, stir until the sugar dissolves. Continue to cook, stirring, until smooth and light brown, about 8 minutes. Add the remaining vanilla and pecan pieces and continue to cook, stirring, until the mixture reaches 234 to 240 degrees F on a candy thermometer or the soft ball stage. Remove from the heat and pour over the cheesecake. Let sauce cool and then slice into individual servings.
Garnish each slice with a dollop of whipped cream and a sprig of mint.
Yield: 12 to 16 servings