Octopus a la Plancha, Marcona Almonds, Arugula, and Jerez Vinaigrette
For the Octopus:
In a large saucepot, combine the onion, 1 head garlic, carrot, celery, orange, 1 rosemary sprig, and bay leaf. Cover with 3 quarts of water, and simmer for 30 minutes. Strain, discard the solids, and season the broth with salt. Reserve. Bring a large pot of salted water with the lemons to a boil. Add the octopus, boil for 1 minute and strain. Wrap each octopus in cheesecloth and simmer lightly in the court bouillon for 1 hour and 15 minutes. Remove the pot from heat and cool at room temperature for 30 minutes. Strain and chill the octopus. Clean off and discard the suction cups from the octopus tentacles. Cut the octopus into 4-inch pieces. Transfer the octopus to a non-reactive container and toss with the olive oil, pepper, the remaining 2 rosemary sprigs, and 4 cloves crushed garlic. Cover the container and store in the refrigerator. Marinate overnight or for at least 4 hours.
For the Almond Purée:
In a medium saucepot, combine the shaved almonds, milk, and sachet and bring to a simmer. Cook the almonds, stirring occasionally until they are tender, about 30 minutes. Discard the sachet and strain the almonds, reserving the liquid. Transfer the almonds to a blender and purée, streaming in the reserved milk to reach a thick, smooth purée. Stream the almond oil into the mixture and season with salt and white pepper.
For the Sherry Vinaigrette:
In a small bowl, whisk together the shallot and Sherry vinegar. Stream in the olive oil, while whisking. Add the oregano and season with salt and pepper.
To Assemble and Serve:
Set the Jade plancha over high heat. Season the Octopus with salt and pepper and sear on all sides. Plate a spoonful of Almond Purée and top with a portion of seared Octopus. Toss the arugula and the oranges in the Sherry Vinaigrette and arrange the salad atop the Octopus. Drizzle some additional Sherry Vinaigrette over the Octopus. Sprinkle the Octopus with the toasted almonds.