Sauté the Vegetables
In a large soup pot, heat the olive oil over medium heat. Add the onion, garlic, carrot, celery, and red bell pepper. Sauté for about 5 minutes, or until the vegetables are soft and the onion is translucent.
Add Herbs and Seasoning
Sprinkle in the dried thyme, oregano, and red pepper flakes if using. Stir and cook for another minute, allowing the spices to release their aroma.
Add Tomatoes and Broth
Pour in the diced tomatoes with their juice, clam juice, and water. Stir well to combine.
Simmer with Potatoes
Add the diced potatoes and bay leaf to the pot. Bring the mixture to a gentle boil, then reduce the heat and let it simmer for about 20 minutes, or until the potatoes are tender.
Add Clams
If using fresh clams, add them to the pot, cover, and cook for 5-7 minutes until the clams open. If using canned clams, add them along with their juice in the last 5 minutes of cooking to heat through without overcooking.
Season and Serve
Season the chowder with salt and black pepper to taste. Remove and discard any unopened clams and the bay leaf.
Garnish
Ladle the chowder into bowls and garnish with fresh parsley for a touch of color and flavor.