Step 1 On medium heat, bring the sugar and one-fourth cup water to a boil, turn down the flame and let simmer for a couple of minutes to reduce and thicken into a simple syrup. Set aside to cool.
Step 2 Whisk together the buttermilk, creme fraiche, corn syrup, lemon juice and 3 tablespoons of the simple syrup.
Step 3Freeze in an ice cream maker according to the anufacturer's instructions. Makes 2 1/2 cups.