Boil the (cleaned) octopus in a classic court bouillon for approximately 2 hours depending on the size.
Let cool and cut into rings.
Boil the potatoes and cut into small cubes.
Prepare a tomato concasse.
Brunoise cut the squashes, then steam and let cool in ice water.
Prepare an emulsion of garlic, extra virgin olive oil, parsley, and lemon juice.
Combine all ingredients.
Season with this emulsion, salt and pepper.
Garnish with several basil leaves.