Heat olive oil in a large cast iron skillet over medium heat.
Dice potatoes, bell pepper and onion. Add potatoes to the skillet and allow to saute for about 10 minutes, or until barely tender. Add onions and peppers to the skillet and cook for another 5 minutes, until tender.
Add garlic and spices to the skillet, and cook for 2-3 minutes.
Pour in canned tomatoes, fresh tomatoes, and harissa (or cayenne/red pepper flakes if using), increasing the heat to medium high to allow the liquid to come to a boil. Reduce heat to bring liquid down to a simmer, stirring occasionally, for 5 minutes. Season with salt and pepper to taste.
Using the back of a large spoon or spatula, make 6 wells in the tomato mixture. Carefully crack an egg in each well, and cover. Continue to simmer for 5-7 more minutes until the eggs are cooked to your liking.
Top with chopped parsley and/or feta, and serve immediately with toasted bread or pita.