Ingredients

• 1 tbsp butter
• 2 ½ cups sugar
• ½ cup water
• 2 cups heavy cream
• 1 cup whole milk
• 2 tsp salt
• 3 egg yolks
• 2 tbsp balsamic vinegar

Instructions

1. In a large, heavy-bottomed, nonreactive saucepan over medium heat, melt the butter with 1 ½ cups of the sugar. Watch carefully as the mixture begins to melt and darken around the edges, stir the with a heatproof spatula to incorporate it. It will look a little sandy, but that’s OK. Continue cooking until the caramel takes on a deep amber color and is a smooth liquid, about 15 minutes.
2. Immediately add the water to stop the cooking.  Caramel can go from being a perfect, smooth brown color–dare we say mahogany?–to being burnt and smoking in a matter of seeonds. Be very eareful when adding the water, because the caramel will splatter when the water hits it, and blisters on your hands just aren’t cute.
3. After the water is in, heat gently, stir over medium, stirring until incorporated and the caramel is a smooth liquid again. Now you work just as you would with your usual custard base: Add the cream, milk, and salt and cook, stirring occasionally, until the mixture is hot but not boiling.
4. Fill a large bowl or pan with ice and water. Place a large, clean bowl in the ice bath and fit the bowl with a fine-mesh strainer.
5. Meanwhile, in a medium bowl, whisk together the egg yolks and the and the remaining 1 cup sugar until blended.
6. Remove the cream mixture from the heat. Slowly pour about half of the cream mixture into the yolk mixture, whisking constantly. Transfer the yolk mixture back to the saucepan with the remaining cream mixture and return it to medium heat. Cook, stirring constantly with a rubber spatula and being sure to scrape the bottom of the saucepan so it doesn’t scorch, until the liquid begins to steam and you can feel the spatula serape against the bottom of the pan, 2 to 3 minutes.
7. Remove the custard from the heat and immediately pour it through the strainer into the €clean bowl you set up in the ice bath. Let cool, stirring occasionally.
8. When the custard has totally cooled, cover the bowl tightly and chil in the refrigerator for at least 1 hour or preferably overnight. Right before you are ready to freeze the custard, add the vinegar (it will curdle the mix if allowed to sit). Transfer the custard to an ice cream maker and spin according to the manufacturer’s instructions. (Don’t pull your hair out if it’s not solidifying all the way in the machine; this is one of the softer ice creams in the book, and the freezer can finish the job.) Transfer to an airtight container, cover and freeze until it reaches the desired consistency. It will keep for up to 1 week.

Source: Humphrey Slocombe Ice Cream Book