Blackberry Cranberry Sauce

Place the cranberries in a medium saucepan with the water, salt and the two sugars on medium high heat. Stir to dissolve the sugar. Bring the mixture to a boil until the cranberries pop and sizzle, about 4-5 minutes. Add the berries and the vinegar, lower the heat to medium, and let the mixture gently simmer, stirring occasionally for 6-8 more minutes, until the liquid is syrupy and almost evaporated. If the mixture is very thick, add up to a quarter cup more water and continue to cook until the sauce is syrupy and chunky. Remove from heat and stir in the vanilla.Cool and serve. Store in a sealed container in the refrigerator for up to 3 days.