Begin by heating the vegetable oil in a large pan over medium heat until shimmering. Add the finely chopped shallots and minced garlic, stirring gently, and sauté until they become translucent and fragrant, about 5 minutes. This step ensures the vegetables release their sweet and aromatic flavors, forming a delicious base for the stew. Next, add the chopped tomatoes to the pan and cook them down slightly until they soften and meld with the shallots and garlic. Be careful not to overcook; the tomatoes should retain a bit of their structure and tanginess. Transfer the sautéed vegetable mixture into a large pot and add the drained cannellini beans. Stir to combine everything evenly. Nestle the chopped chorizo pieces among the beans and vegetables, allowing their spicy, smoky essence to infuse the stew. Cook the pot over low heat for 20 minutes, stirring occasionally to prevent sticking and to encourage the flavors to meld beautifully. Alternatively, for a richer, slow-cooked texture, place the pot in a preheated oven at 180ºC (350ºF) and bake for 30 minutes. A handy tip: this stew tastes even more delicious the next day when reheated, as the beans have absorbed the chorizo's smoky flavors and the sauce has thickened. For an added touch of freshness before serving, sprinkle a pinch of chopped parsley on top.