Heat raspberries with water in a sauce pan over medium high heat until boiling. Reduce heat to a simmer. Cook about 5 minutes until berries have burst and become pulpy. Strain berries over a bowl with a fine mesh sieve. Mash the berries against the sieve with the back of a spoon to release the juices. (You can keep the raspberry pulp for pancake or waffle sauce!)

Chill the juice in the refrigerator until cool.

This makes 2 cocktails. Chill 2 highball glasses. Add some ice, 4 ounces raspberry juice, 2 ounces vodka, 4 ounces soda water and a splash of rhubarb bitters. Add sweetener to taste.