Heat up the olive oil in a large pot over medium heat.
Once the oil has warmed, add the ground sausage to the pot. Using a spatula or meat masher, break it down into crumbles as it cooks.
When cooked, remove the sausage from the pot with a slotted spoon; set it aside.
Bring the onions, peppers, zucchini, and parsley to the pot. Hit them with a generous amount of salt and let them all simmer for about 5-8 minutes, or until the veggies are tender.
Stir in the garlic, letting it cook for about 30 seconds.
Spoon the tomato paste into the pot, and then add the chicken broth; give it a good stir until the tomato paste melts into everything.
Pour the tomato sauce into the pot, then stir in the sausage.
Cover and let it all simmer on low for about 30 minutes.