These tiny treats are a perfect addition to a late-night sweets table.
Bring 3/4 cup milk, cream, sugar, vanilla-bean seeds and pod, and salt to a boil in a small saucepan over high heat. Turn off heat, and let stand 10 minutes to steep. Meanwhile, in a medium bowl, sprinkle gelatin over remaining 2 tablespoons milk. Let stand for 5 minutes to soften.
Return cream mixture to a full boil, then remove from heat and slowly whisk about 1/3 cup hot cream mixture into gelatin until gelatin is fully dissolved. Whisk in remaining hot cream mixture. Strain through a fine sieve.
Place creme fraiche in a medium bowl and slowly whisk in warm mixture until it is completely smooth. Let stand until barely warm and slightly thickened, whisking occasionally, about 30 minutes. Whisk again (to suspend vanilla beans) and divide among eighteen 1-ounce molds. Refrigerate until completely set, about 3 hours.
To serve, top chilled panna cottas with small clusters of spun sugar. Use a small paintbrush to transfer pieces of gold leaf to the top of the spun sugar.
To fill the panna cotta molds without mess, transfer the mixture to a squeeze bottle. Panna cottas can be refrigerated up to 1 day.