Add the remaining olive oil to the sauté pan and over a low heat fry off the chopped shallots, celery, and carrots for 10 minutes until softened. Using your wooden spoon scrape the base of the pan, this will add instant flavour. Scrape in the minced garlic and tumble in the 3 grain ‘Rustico’ mix. Stir and coat all the grains in the softened vegetables and pour in the wine. Cook the wine off for 2 minutes then stir in the tomato puree followed by the stock and passata. At this stage you can add the Parmigiano Reggiano rind. I like to chop the rind into tiny cubes. Stir and season well with salt, pepper, chilli flakes and bay leaf.