A perfect Manhattan with bittersweet liqueur rather than aromatic bitters and a balancing dash of sweet maraschino liqueur.
If you can't obtain Picon...
Didn’t have Amer, so on the fly I substituted in Aperol in slightly short pour. I followed with Rittenhouse Rye, Noily Prat Extra Dry, Cocchi di Torino, and an off-brand maraschino liqueur. The Brooklyn was still wonderfully complex. I found it a delightful change of pace to my Manhattan.