Bring the Maraschino Luxardo to a simmer over medium heat. Once you see the first signs of a simmer turn off the heat and add the fresh cherries, almond extract, and the optional 2-3 tablespoons of agave.
Allow the fruit and liquid to cool completely before transferring it to a large canning jar and storing in the refrigerator.
Let the cherries macerate in their boozy liquid for at least 2 weeks. Every 2-3 days remove the jar from the refrigerator, give it a shake and a swirl then place it back to marinate more.