Step 1: Prepare Your Vegetables. Begin by finely dicing your onion, carrots, and celery. Mince your garlic. Core and chop your cabbage into bite-sized pieces; they will shrink, so don't make them too small. Chop your bell pepper.
Step 2: Sauté Aromatics. In a large pot or Dutch oven, heat 2 tablespoons of olive oil over medium heat. Add the diced onion, carrots, and celery. Sauté for 5-7 minutes, until the vegetables begin to soften and the onion is translucent.
Step 3: Add Garlic and Bell Pepper. Stir in the minced garlic and chopped bell pepper. Cook for another 2-3 minutes until fragrant. Be careful not to burn the garlic, as it can turn bitter.
Step 4: Introduce Tomatoes and Spices. Pour in the canned diced tomatoes (undrained), tomato paste, dried oregano, dried thyme, bay leaf, and a pinch of red pepper flakes (if using). Stir well, scraping up any browned bits from the bottom of the pot. Cook for 5 minutes, allowing the tomato paste to caramelize slightly and deepen in flavor.
Step 5: Add Cabbage and Broth. Add the chopped cabbage to the pot. It might seem like a lot, but it will wilt down significantly. Pour in the vegetable broth and water. Season generously with salt and freshly ground black pepper. Bring the mixture to a boil.
Step 6: Simmer to Perfection. Once boiling, reduce the heat to low, cover the pot, and let the soup simmer for at least 30-45 minutes, or until the cabbage and other vegetables are tender. The longer it simmers, the more the flavors will meld together.
Step 7: Finish and Serve. Remove the bay leaf. Taste the soup and adjust the seasoning as needed. You might want a little more salt, pepper, or a splash of vinegar or lemon juice to brighten the flavors. Ladle into bowls and garnish with fresh chopped parsley or dill, if desired. Serve hot and enjoy!