Combine cocoa, chocolate, sugar, salt and water in medium saucepan. Stir and heat until sugar and chocolate are dissolved. Boil 3 minutes. Remove from heat and beat vigorously with electric beater. Beat eggs into mixture. Return to heat. Add butter and beat again with electric beater. Let simmer over lowered heat 10 minutes. Add vanilla and let cool. Pour into quart jar and store in refrigerator for
use in various chocolate drinks and as a desert sauce. Makes about 1 quart of syrup.