Makes ¾ cup
1/2 cup sugar
1/4 cup flavored liquid (apple juice, cocoa cola, chocolate milk, heavy cream, etc)
4 T butter
1/2 tsp vanilla
1/2 tsp salt
1. Make a dry caramel: Heat the sugar in a medium heavy-bottomed saucepan over medium-high heat. As soon as the sugar starts to melt, use a heatproof spatula to move it constantly around the pan—you want it all to melt and caramelize evenly. Cook and stir, cook and stir, until the caramel is a deep, dark amber, 3 to 5 minutes from when the sugar starts to melt.
2. Once the caramel has reached the target color, remove the saucepan from the heat. Very slowly and very carefully, pour in the liquids. The caramel will bubble up and steam; stand away until the steam dissipates. Use the heatproof spatula to stir the mixture together.
3. Add the butter, vanilla and salt, continue stirring. If it is at all lumpy or if there are any clumps of hardened caramel floating around the sauce, put the saucepan back over medium heat and heat the mixture, stirring constantly, until the mixture is smooth.
4. Let the caramel cool before using. It will keep in the refrigerator, in an airtight container, for up to 2 weeks.