In a large stock pot, heat olive oil over medium-high heat. Sear chicken breasts for about 2 minutes per side until lightly browned, then remove and set aside.

Lower heat to medium. Sauté onion, carrot, celery, and fennel for about 8–12 minutes, stirring occasionally, until softened and starting to caramelize.

Add minced garlic, salt, pepper, dried oregano, and bay leaves (if available), cooking for 1–2 minutes until fragrant.

Stir in chopped tomatoes, their juices, and the rinsed butter beans. Then add the stock paste and cook 1–2 minutes to meld the flavors.

Pour in water and bring the soup to a simmer over medium-high heat. Once simmering, nestle in the chicken breasts, cover pot partway, and cook over medium-low for 15–20 minutes until chicken is cooked through.

Meanwhile, if using orzo, cook it separately to al dente in salted water and drain.

Remove the chicken breasts and shred with forks or dice into bite-sized pieces; return to the pot. Squeeze in the lemon juice and stir. Taste and adjust seasoning with salt and pepper as needed.

Serve the soup hot. Optionally add a scoop of orzo into each bowl. Garnish with crumbled feta, minced parsley, extra lemon, or chili flakes for a Greek twist.