In a large Dutch oven, heat the olive oil over medium heat. Add the pearl onions and sauté until they are lightly golden and soft, about 5 minutes. Stir in the minced garlic and cook for an additional 1 minute until fragrant.
Increase the heat to medium-high and add the beef chunks to the pot. Season generously with salt and pepper. Sear the beef on all sides until browned, about 6-8 minutes.
Once the beef is browned, add the cinnamon stick and stir to combine.
Pour in the diced tomatoes and tomato paste, stirring well to combine all the ingredients.
Add the baby carrots and cover the pot. Reduce the heat to low and let the stew simmer for 2 to 2.5 hours, or until the beef is tender and easily pulls apart with a fork.
Once the beef is tender, remove the cinnamon stick. Stir in the grated lemon zest and dried oregano, adjusting salt and pepper to taste. Finally, sprinkle crumbled feta cheese on top before serving.
