Place the cream, milk, turmeric, vanilla, honey and salt in a heavy saucepan and slowly bring to the boil, stirring occasionally.
Whilst the above is heating, whisk together the egg yolks and brown sugar in a large bowl, until thick and light in colour.
Slowly pour the hot milk and cream mixture into the egg mixture (whilst whisking) and then return to pan. Slowly warm over a low heat, stirring continuously until thick (do not boil, or otherwise it will split).
Sieve the mixture into a large bowl and leave to cool. Once the mixture has cooled, stir in the mustards and place in the fridge (stir regularly until chilled).
Put the mixture in an ice cream maker for 30 to 45 minutes. Transfer the mixture to a plastic container and place in the freezer for about 5 hours, or until frozen.