01 - In a medium saucepan, mix cranberries, mixed berries, sugar, orange juice, water, orange zest, and salt.
02 - Heat over medium-high, stirring occasionally until the mixture reaches a boil.
03 - Reduce heat to medium-low and simmer for 10 to 12 minutes, stirring occasionally until cranberries burst and sauce thickens.
04 - Mash berries with a spoon or potato masher for a smooth sauce, or leave as is for a chunkier consistency.
05 - Remove saucepan from heat and stir in vanilla extract if using.
06 - Allow sauce to cool to room temperature; it will thicken further as it cools.
07 - Serve chilled or at room temperature alongside meats, pancakes, or desserts.