Start by cleaning the squid, removing the head and innards while rinsing it thoroughly under cold water. Ensure to keep the body intact. Finely chop the squid legs and set them aside for the stuffing.

In a medium pan, heat a splash of olive oil over medium heat. Add the chopped squid legs, red onion, green onion, and long sweet green pepper. Sauté for about 5 minutes, stirring until the vegetables soften. Incorporate the garlic, zucchini, carrot, celery, rice, and tomato, continuing to cook for an additional 3-4 minutes until fragrant. Pour in some water, season with salt and pepper, and simmer for about 15 minutes until the rice absorbs most of the liquid.

Carefully spoon the prepared stuffing into the squid, filling it without overstuffing—leave a 2 cm gap at the top for expansion. Secure the openings with toothpicks to prevent the filling from spilling out during cooking.

In a large pot, heat a bit of olive oil and sauté the remaining red onion for about 5 minutes until it's translucent. Gently place the stuffed squid in the pot, searing them for about 2-3 minutes on each side until they begin to color. Add the tomato passata, some water, sweet red pepper, and a bay leaf. Season lightly and stir to combine, creating the base for your rich sauce.

Cover the pot and simmer on low heat for 50 minutes to 1 hour, allowing the sauce to thicken and the flavors of the Stuffed Squid With Rice and Vegetables to meld beautifully. The squid should be tender when done—check for doneness by gently poking it.

After cooking, let the squid rest in the sauce for an additional 20 minutes for maximum flavor absorption.