Begin by washing your zucchini and bell peppers. Slice the zucchini into rounds and the peppers into strips. Next, in a pan over medium heat, cook the Italian sausage. Break it into smaller pieces and cook until browned. This step adds flavor and texture to the dish.

Once the sausage is browned, it's time to assemble everything. In your slow cooker, begin by layering the zucchini at the bottom. Follow that with the green bell peppers and celery. These veggies create a beautiful, vibrant base filled with nutrients.

Once the vegetables are layered, add the browned Italian sausage on top. The sausage will release its delicious, savory juices as it cooks, soaking into the veggies below.

Next, open those cans of crushed tomatoes. Pour them evenly over the sausage and vegetables. The acidity from the tomatoes balances out the richness of the meat and brings depth to the dish. Don't forget to sprinkle in the sugar; this helps balance the flavors beautifully.

Sprinkle the sea salt, oregano, Italian herb blend, dried basil, garlic powder, and red pepper flakes over the entire mixture. Use a spoon to gently stir everything, ensuring the spices are well-distributed.

Cover your slow cooker and set it on low heat. Let it cook for about 6-8 hours or until the vegetables are tender. Smell that aroma wafting through your home? That's the anticipation of deliciousness!

Once the cooking time is up, give it a good stir. Lastly, sprinkle the freshly grated Parmesan cheese and chopped fresh basil on top before serving. It adds a final layer of flavor that’s simply irresistible.