To a bowl, prepare an ice bath by adding 10 or so ice cubes and adding a few splashes of water. Set a slightly smaller bowl inside the bigger bowl and set a sieve or strain inside the smaller bowl. Set the whole ice bath contraption aside.
To a medium saucepan, add the heavy cream and sugar; heat over medium until the cream reaches a slight simmer and the sugar dissolves. Once it reaches the simmer, remove the pan from the heat.
In a medium mixing bowl, beat the egg yolks together, thoroughly. Next you’re going to temper the cream mixture. Whisking the entire time, add about 1/4 cup of warm cream to the egg yolks. Add the remainder of the cream to the egg yolk mixture and whisk. Return the entire mixture back to the medium saucepan and place over low heat. Cook the cream and yolk mixture, stirring constantly, until the thermometer reads 170 to 175 degrees F and the mixture appears thick and coats the back of the spoon.
Pour the mixture through the sieve into the bowl. Add the honey, vanilla and buttermilk. Stir constantly until the mixture becomes room temperature. Wrap the bowl in plastic and transfer it to the fridge for 4-5 hours, or overnight, until very cold.