I love to hear of sustainable cocktail making (especially finding a use for leftover or byproducts)... I did something similar recently using the whey leftover from making ricotta in a riff on the "Ramos Gin Fizz" — it used Tequila as the base spirit and it included agave syrup, vanilla essence and egg white for added stability. Yum!
A very interesting sipper (and one I wished I'd tried when in New Orleans instead of waiting till now.
As others here have commented, I found it a bit on the sweet side so will revisit by addressing those ratios... perhaps 45ml Rye, and just 20ml sweet vermouth, 10ml Benedictine. I may also increase the amount of Peychauds (or even a split of that and another bitters — Reagan's Orange or Angostura).
I adore that Boadas glass and am very envious...
I've used Gaztelu Vermut Rojo ( made since 1899) which I find to be nicely aromatic and not at all too sweet.
Checked my 1926 copy of "Harry's ABC of Mixing Cocktails" and the listing reads:-
1 white of a Fresh Egg, 2 dashes of Curaçao (orange), 1 teaspoonful of Grenadine, ⅔ Canadian Club whisky. Shake well. Strain into cocktail glass. (Recipe from Ritz Hotel, London.)
...no lemon juice, raspberry liqueur, nor Absinthe!