Before you start cooking, prepare all your ingredients. Dice the onion and bell pepper into small, uniform pieces. Mince the garlic cloves finely. Measure out all your spices and have the canned tomatoes and tomato paste ready. This 'mise en place' helps ensure a smooth cooking process.

Heat the olive oil in a large, deep skillet over medium heat. Add the diced onion and cook for 5-7 minutes, stirring occasionally, until it softens and becomes translucent. Add the diced bell pepper and cook for another 5 minutes until tender. Next, stir in the minced garlic, smoked paprika, cumin, and chili powder (if using) and cook for just 1 minute until fragrant.

Stir in the tomato paste and cook for 2 minutes, stirring constantly. This deepens the tomato flavor. Pour in the crushed tomatoes, then stir in the salt and black pepper. Bring the sauce to a gentle simmer, then reduce the heat to low, cover the skillet, and let it simmer for 15 minutes to allow the flavors to meld and the sauce to thicken slightly.

Uncover the skillet. Using the back of your spoon, create six small indentations or 'wells' in the simmering tomato sauce. Carefully crack one egg into each well. Be gentle to keep the yolks intact. Cover the skillet again and continue to cook for 8-12 minutes, or until the egg whites are set and the yolks are still runny (or to your desired doneness).

Remove the skillet from the heat. Garnish generously with fresh chopped parsley or cilantro and crumbled feta cheese, if using. Serve immediately directly from the skillet, or carefully spoon individual servings onto plates. Shakshuka is traditionally served with crusty bread for dipping into the rich sauce and runny yolks.