For dairy free ice-cream, substitute full fat coconut milk for the dairy, or follow the same ratios as above but use full fat coconut milk and coconut cream.
Combine heavy cream, milk, honey, vanilla bean, and rosemary sprig in a saucepan. Warm on medium heat, stirring all the while. Remove from heat once bubbles form along the edges of the pan. Cover and let the rosemary sprig steep for 30 minutes as if you’re making a simple syrup or infusion.
While rosemary is steeping, whisk egg yolks and salt until yolks are light and airy.
Remove rosemary sprig and vanilla bean pod from your cream mixture after 30 minutes and return to a gentle simmer. Once simmering, slowly pour this warmed mixture into the bowl with egg yolks and salt. Whisk until evenly blended and light. This is your custard or the ice-cream base.
Move the custard back into the saucepan on low to medium heat. Stir continuously until the custard thickens and forms a coat on the back of a spoon that holds when you run your finger through it. Or test the temperature with an instant read thermometer. It should register 165 F to 170 F.
Cover and place it in the fridge until cool. This can take six to 12 hours. It’s possible to shorten cooling time by placing the bowl in a larger, second bowl of ice water (like a double boil system but a double cooling system).
Once the custard is completely cool, transfer it to your ice-cream maker and follow the maker instructions. If you want to be sure all the bits of egg that haven’t dissolved in the mix are out, strain the custard through a find mesh colander when transferring to your ice-cream maker.