Place the sugar in a heavy saucepan over medium heat.
Don't stir the sugar. After about 3 minutes or so, the sugar will begin to melt around the sides. Use a whisk or a heat-proof spatula to stir the sugar so it all melts or swirl the saucepan around.
When it foams in the middle and small bubbles appear, add ⅓ of the cream and whisk the mixture continuously. DO NOT ADD ALL THE CREAM AT ONCE! It will bubble up and steam, but just keep whisking it. Then add a little more cream and continue whisking.
Take the saucepan off the heat and add the remaining cream. Whisk until it’s well combined.
Add the butter and whisk again to combine everything.
Finally add the salt and whisk again. When it cools a bit, you can taste it to see if you want to add more salt.
Pour the caramel into a bowl to cool completely. Set aside.
Make the Ice Cream
Whip the cream and the vanilla together to stiff peaks.
To the whipped cream, add the sweetened condensed milk and ¾ cup of the cooled caramel sauce. Mix until combined.
Pour ⅓ of the ice cream base into the pan. Add about ⅓ of the pretzels on top. Then drizzle some caramel sauce over the pretzels.
Repeat the process 2 more times, adding 2 more layers. If you wish, you can use a knife to swirl the caramel throughout after adding the last layer.
Then cover with plastic wrap, touching the surface. Then cover with aluminum foil and freeze for at least 12 hours or overnight.
Enjoy!
Notes
If you want to buy caramel sauce for this recipe, make sure it's thick and not too runny. I would avoid using the caramel found in squeeze bottles because it's a bit runny.
The recipe for the salted caramel sauce makes about 1 ½ cups, so there will be some left over. You can store it in a glass jar in the refrigerator for up to a month. It will thicken as it cools.
This ice cream can be kept in the freezer for up to about 2-3 weeks as long as it’s well covered.
This is a soft-serve ice cream. It needs at least 12 hours to set (overnight is even better). Because it has a lot of caramel it won’t freeze rock-hard like regular ice cream and it won’t get icy at all.