Ingredients

2 cups sugar 

1/2 cup water 

1 cup heavy cream 

1/2 vanilla bean, split lengthwise and scraped 

1 teaspoon freshly squeezed lemon juice 

2 tablespoons unsalted butter 

Preparation

In a 2-quart saucepan over medium heat, stir sugar and the water until sugar has dissolved. Without stirring, cook until dark amber, about 20 minutes; wash down sides of pan with a wet pastry brush to prevent crystals from forming.

Reduce heat to low. Carefully add the cream in a steady stream; stir with a wooden spoon when bubbling subsides. Add vanilla bean and scrapings; stir in lemon juice and butter. Remove from heat; discard vanilla pod before serving.