This is the only recipe I have found that includes dry vermouth. Is there a specific reason that you added that to the recipe?

Interesting! I only said that because I've seen photographs of the original bottles and the color certainly looks different although of course it may have changed over this many years. I asked my father and he said that the current version tastes a lot better than the old one did. I've heard a few people complain about the color but I'm much more interested in the flavor. Creme Yvette in its current form is a masterpiece. My bottle of Rothman and winter sits untouched. ?

I believe that the original creme Yvette was a different color, and had inferior ingredients to the new one. That's why the color of the blue moon and aviation is wrong, but they taste a lot better than with creme de violette!