Heat a medium sauce pan on the stove until it's warm.

Add the ketchup and the El Pato Red Sauce to the pan and stir to combine.

Stir in the brown sugar, and make sure it's mixed well.

Turn the stove to medium high heat, and bring it to a boil.

Once it reaches a boil, reduce it to a simmer.

Cover it and cook at a summer for thirty minutes, stirring ocassionally.

Use immediately.

To store for later use, allow the mixture to cool to a room temperature, and then store in an air-tight container for up to two weeks in the fridge, and use as needed.