New Zealand Mayonnaise - cooking recipe

Ingredients

3 eggs, beaten
1 cup vinegar (scant cup)
1 cup sugar (heaped cup)
3 teaspoons flour (heaped cup)
3 teaspoons mustard
3 teaspoons salt
1 1/2 cups water
1 tablespoon butter

Preparation

mix together all ingredients except butter.
add butter and place in double boiler.
stir occasionally.
chill before serving.