Step 1

Pour the stout into a medium saucepan and heat to boiling. Reduce heat to a rapid simmer and cook until the stout is reduced by half.

Step 2

Stir in the brown sugar and vanilla. Heat to boiling, reduce heat to a rapid simmer and let the mixture cook 8-10 minutes without stirring until sauce turns a deep amber and bubbles start to grow and expand. Mixture will be hot like lava, so be careful.

Step 3

Remove from heat and add the butter, cream and salt and stir carefully until fully combined. Transfer to a resealable glass storage jar and let the mixture cool to room temperature. Keep in the refrigerator for up to two weeks.