Break down the gelatin and place into a bowl, then cover it in water and let it sit for 5-10 minutes to soften.
Mix half the cream (1¼ cups) and the buttermilk into a large container and set aside.
Pour the rest of the cream, the sugar, and the salt into a large saucepan over medium heat. Bring it to a boil, whisking continuously until sugar dissolves, then remove from heat.
Stir in the gelatin and whisk until dissolved, then pour it into the cream and buttermilk mixture.
Place the mixture into the fridge to set for at least 2-4 hours.