A stunning seafood antipasto of tender octopus simmered with aromatics, pressed into a tight cylinder, chilled until set, and sliced paper-thin with lemon, pink peppercorns, and fruity olive oil.
Bring a large pot of water to a boil with onion, carrot, celery, bay leaf, and peppercorns. Dip octopus tentacles into boiling water 3 times to curl them, then submerge completely. Lower heat, cover, and simmer very gently for 50-60 minutes until tender.
Cut the warm octopus into large chunks. Pack tightly into a clean cut-plastic bottle or cylindrical press with drainage holes at the base. Press down firmly with a weighted lid or pestle to squeeze out excess liquid and compact the natural gelatin. Refrigerate overnight for at least 8 hours.
Unmold the gelatin-bound octopus cylinder. Using an electric meat slicer or very sharp slicing knife, cut across into paper-thin, translucent mosaic rounds.
Arrange rounds overlapping on chilled platters. Drizzle generously with lemon juice, fruity olive oil, crushed pink peppercorns, parsley, and flaky sea salt.