Step 1

Combine the butter and half and half in a double boiler or a saucepan that you've set over another larger pot with simmering water. Warm until the butter is melted. Whisk together.

Step 2

Add the chocolate, espresso, brown sugar, vanilla, and sea salt to the mixture and bring to a simmer; whisking continuously until smooth.

Step 3

Use an immersion blender (or pour mixture into a countertop blender) and blend until smooth and shiny.

Step 4

Cool.slightly before serving warm over your favorite ice cream.

Step 5

Refrigerate to store; heat in warm water or microwave on low power before using.