In a saucepan, combine the raspberries and water. Bring to a simmer over medium high heat. Turn down the heat to low and let simmer for about 5 minutes to reduce the liquid. Strain the juice, pressing gently on the berries to extract all the juice. Measure the juice.
Return the juice to a clean saucepan and place over medium heat. Add an equal amount of sugar, stirring to dissolve. Remove from the heat and allow to cool. Add the rose water. The syrup will keep for about 3 weeks in the fridge.
Raspberry Rose Cocktail
To make the cocktail, combine the gin, Lillet Blanc, raspberry rose syrup, lemon juice, and lavender bitters in a cocktail shaker. Add ice, cover, and shake for 10 to 15 seconds. Strain into a coupe glass. Garnish with dried rose buds. Enjoy!