Over medium heat in a stove top sauce pan, melt 4 tablespoons of butter.
Whisk in the vinegar. Over low heat whisk in the flour, lemon juice and seasonings. Whisk until the ingredients are fully incorporated.
Beat the egg yolks in a separate bowl, then pour 2 tablespoon of the warm liquid into the beaten egg yolks to temper them.
Slowly drizzle the egg yolks into the vinegar mixture, whisking continually. Cook for 2 minutes.
Remove the saucepan from the stove top and beat in 1 cup of granulated sugar.
Beat for 2 minutes or until the dressing has thickened and is light yellow in color. Cool completely.
After the dressing has cooled pour over the chopped cole slaw and green onions. Mix well.
Let the cole slaw chill in the fridge for at least 4 hours.
Taste and adjust the salt and pepper, if needed, and stir well before serving.