This cocktail is delightfully sweet, with just a little kick, and makes good use of raspberries that are slightly bruised. NOTE: This recipe requires overnight preparation.
4 pints fresh raspberries
3⁄4 cup sugar
6 oz. vodka
1. Put raspberries into a large bowl set over a large pot of simmering water over low heat. Cook undisturbed until berries begin to collapse into their juices, 3–4 hours.
2. Using a rubber spatula, gently stir berries to just wet them with their juices. Continue cooking berries undisturbed until most of their juices have been released, about 2 hours more.
3. Pour berries and juice into a clean jelly bag suspended over a bowl and allow to drain undisturbed overnight. (Don't squeeze bag, or cordial will be cloudy.)
4. Meanwhile, heat sugar and 1⁄2 cup water together in a small pot over medium-low heat, stirring until sugar dissolves, 3–5 minutes. Cover and simmer for 2 minutes more. Remove from heat, uncover, and set aside to let cool.
5. Combine juice (you should have about 1 cup), syrup, and vodka in a pitcher, then pour into a 16-oz. bottle. Add a few fresh raspberries. Refrigerate for up to 3 months.