Heat the olive oil in a large pot over medium heat.
Add the diced onion and sauté for 3-5 minutes until translucent.
Stir in the minced garlic and cook for an additional minute.
Add the carrots and celery, cooking for another 5-7 minutes.
Incorporate the bell pepper, potatoes, and zucchini, stirring well.
Pour in the vegetable broth, followed by the thyme and bay leaf.
Bring the mixture to a boil, then reduce heat to let it simmer.
Season with salt and pepper, adjusting to your taste preference.
Let the stew simmer for 30-40 minutes, stirring occasionally.
Remove the bay leaf before serving.