Salted Butter Caramel Sauce

6 tablespoons (3 ounces, 85 grams) 
3/4 cup (150 grams) sugar
1 cup (250 m) heavy cream, warmed
1/2 teaspoon vanilla extract
1/2 teaspoon flaky sea salt

Melt butter and sugar together in a large saucepan over medium heat (one that will hold at least 4 quarts or preferably larger).

Continue to cook the sugar and butter together, stirring frequently, until the color is deep golden brown and it starts to smoke.  For best results, cook the mixture until it smells a little smoky, too, but be careful to find the balance between well-browned and the moment before it's burnt, which is when it's ready to have the cream added; it should be the color of an old copper penny.

Immediately remove from heat and gradually pour in the warm cream, stirring constantly, until smooth.  Mix in the vanilla and salt.

Note: If the sauce seizes up when you add the cream, you've probably added it too quickly or it wasn't warm enough.  You can gently warm the sauce over low heat and stir in hardened caramel until dissolved; strain out any stubborn bits that remain.

The sauce can be made up to two weeks in advance and stored in a jar in the refrigerator.  Rewarm by placing the jar in a saucepan of warm water or in a microwave oven.

Makes about 1 1/2 cups.

From DavidLebovitz.com