In a small saucepan, combine cranberries, water, sugar, and vanilla extract. Give it a quick stir and bring to a boil over medium/high heat (watch it or it will boil over). Reduce the heat to medium and cook until the cranberries burst (you'll hear them. It's so cool), soften, and wrinkle a bit. Remove from heat and allow it to come to room temperature (cranberries and all). Strain the cranberries, pressing down on the solids to extract as much liquid as possible. Discard the cranberries or save for cheesecake topping. Pour into a glass container with a tight-fitting lid.
Makes about 2 cups of simple syrup.
For the Cranberry Tangerine Fizzy:
To an 8 ounce glass, add the quartered tangerines and cranberry simple syrup. Muddle with a muddler or back of a wooden spoon until the tangerine slices are very fragrant and release their liquid. Add ice over the tangerine/simple syrup mixture and top with seltzer. Give it a quick stir and garnish with cranberries, if desired.
The calories shown are based on the the recipe making 2 cups of syrup, with 1 serving being 2 tablespoons of syrup in each drink. Since different brands of ingredients have different nutritional information, the calories shown are just an estimate.