1) Cook in bouillon for 2 hours on low simmer. Chill, rub in spices and grill.
2) Steam for 2 hours at 95ºC/203ºF. Chill, rub in spices and grill.
3) Sous-vide cooking in spices for 5 hours at 77ºC/171ºF. Remove from bag and drain. Chill to rest and grill or bbq. Sous vide cooking is the process of sealing food in a vacuum sealed bag – and then cooking that food in temperature-controlled water. In French, the term translates to "under vacuum.”
Octopus shrinks a lot during cooking, losing about two-thirds of its weight.
Hold the octopus under cold running water. If the head/hood is still attached, begin with it flipped inside out to make sure that any remaining entrails are washed away. Then turn the head back the right way around to rinse off. Remove the eyes and beak and discard, save the hood. Cut in between each tentacle (keep whole if using baby octopus). Pat dry the octopus and rub in spices and crushed garlic cloves. Bag using vaccum sealer bags only and cook. Remove from bag, drain and discard liquid. Chill to relax.
Sous-Vide Method: Bag potatoes, season with salt, butter, chopped ginger and a fresh thyme. Vacuum seal and cook at 85ºC/185ºF for 2.5 hours. Remove from bag and spread over a baking tray lined with silicone mat or parchment, and cool. Discard herbs and ginger. Cut potatoes in half and rub in olive oil, spices and herbs. In a hot and large frying pan (make 2 or 3 batches) drizzle some olive oil and arrange potatoes flesh side down. Throw in some butter and give a good caramelization. Then, add diced chorizo and sauté potatoes moving them around the pan. When chorizo has release its fat, remove from the heat and add chopped parsley. Transfer in a baking tray and keep warm. Save remaining fat and bits left in the pan to brush the grilled octopus.
Oven Roasting Method: Sauté diced chorizo for a few minutes, save fat and reserve chorizo. Rub raw potato halves with chorizo fat and olive oil. Add spices, chopped herbs and salt. Spread over a sheet pan or 2 (do not overcrowd). Roast in a 390ºF/200ºC oven for about 40 minutes or until done. Remove from oven and throw in chorizo and parsley. Keep warm.
Emulsion lemon juice and olive oil with a whisk. Add remaining ingredients, and season with salt and pepper. Vinaigrette can be kept refrigerated for up to 2 weeks. Leave out for about 30 min and shake before using.
Heat up grill until it smokes. Grill the previously cooked octopus in both sides using a hot grill press or use a heavy pan. Brush grilled octopus with the saved chorizo fat and slice out the thickest part of the tentacle. Arrange a few roasted potatoes along with chorizo dices on plate. Add grilled octopus and season with lemon vinaigrette and serve!