For the quince syrup:
Place crushed ice in a stemmed rocks glass. In a shaker, combine bourbon, lemon juice, quince syrup, and bitters. Shake gently, pour over ice, and garnish with cherries.
For the quince syrup:
Combine sugar and quince and let sit overnight to macerate. In a stock pot, warm mixture on medium-high heat. Once it starts to bubble, reduce temperature to medium-low and simmer until it achieves a rosy hue and sticks to the spoon like honey (about two hours). Use a sieve to drain the syrup from the fruit.
