Step 1
Pour water into a small saucepan, then gently whisk in the sugar, cocoa, and salt.
Step 2
Bring mixture to a boil, stirring occasionally, for several minutes.
Step 3
Reduce heat and cook for 1 minute.
Step 4
Remove from heat and stir in vanilla. Cool. Store in the refrigerator in an airtight glass container.
Step 1
Fill a cocktail shaker with ice. Pour in vodka and chocolate syrup. Put the top on the shaker and shake well to thoroughly mix and chill the drink.
Step 2
Strain into martini glasses and garnish with raspberries, if desired. Serve immediately.
*Syrup will keep for several weeks in the fridge.