Heat the olive oil in a large saucepan or deep skillet over medium heat. Add the chopped onion and cook for 4 to 5 minutes until soft and translucent.

Stir in the minced garlic and sliced courgettes. Sauté for about 3 to 4 minutes until the courgettes begin to soften slightly at the edges.

Add the drained butter beans, chopped tomatoes, vegetable stock, and dried oregano to the pan. Season with salt and black pepper, then stir well to combine all ingredients.

Bring the liquid to a gentle simmer, then reduce the heat to medium-low. Cover and let it simmer for 10 minutes, allowing the flavors to meld and the courgettes to become fully tender.

Remove from heat, taste to adjust seasoning if necessary, and stir in the fresh chopped parsley right before serving.