Caramelize the sugar

• Place the brown sugar and salt in a saucepan.
• Bring to the stove over medium-high heat, stirring constantly so the sugar caramelizes without burning.

Add the hot water

• Very carefully pour in the hot water.
• Stir until the caramel dissolves completely into the water.

Finish the sauce

• Remove the pan from the heat.
• Pour in the condensed milk and mix well.
• Stir in the vanilla extract.

Cool and store

• Let the mixture cool completely.
• Transfer to a bottle and store in the fridge for 2 to 3 weeks.