Combine the heavy cream, creme fraiche, lemon zest and vanilla scrapings in a saucepan. Bring to a simmer and remove from the heat. In a heat-proof mixing bowl, whisk the egg yolks with the sugar until lightened. Mix in the marmalade. Then pour in the hot cream mixture and stir for 5 minutes and cool in an ice bath. Process in an ice cream machine and freeze.
