Shell prawns and cook for 3 minutes per side in a non-stick pan with a little oil. Set aside 4 of them and finely cut the others. Work ricotta cheese using a fork to make it creamier, add it to the prawn tartare and add salt and pepper.
Blend the celery with half a garlic clove and oil, then drizzle in to obtain the texture you prefer. Add salt and pepper.
Cook Sea Urchin pasta in boiling salted water for 2 minutes, stirring gently. Drain using a skimmer and empty each piece of all cooking water.