½tspapple cider vinegar or fresh lemon juice, optional
The rind of parmesan cheese
(Add in any other vegetables you have on hand)
Heat the oil in a stockpot, or heavy-based saucepan on medium heat. Add the onions, carrots, celery, and tomato paste. Cook, stirring often until the vegetables have softened and the onions are translucent about 8 to 10 minutes.
Add the garlic, fennel, black pepper, 1/2 teaspoon of salt, and the red pepper flakes. Cook, while stirring, for one minute.
Pour in the canned tomatoes and their juices as well as the stock.
Add the potatoes, cabbage, and bay leaves. Raise the heat to medium-high and bring the soup to a boil. Partially cover the pot with a lid, and then reduce the heat to maintain a low simmer. Now add in the rind of the parmesan cheese.
Simmer for 20 minutes or until the potatoes, and other vegetables are tender. Add the frozen peas and cook for five more minutes.
Remove the pot from the heat and remove the bay leaves and parmesan rind. Stir in the cider vinegar (or lemon juice). Taste and season with more salt, pepper, or vinegar.