best shakshuka

Ingredients

• 2 tablespoons extra-virgin olive oil
• 1 cup chopped yellow onion
• 1 red bell pepper, stemmed, seeded, and diced
• ¼ teaspoon sea salt, plus more to taste
• Freshly ground black pepper
• 3 garlic cloves, minced
• ½ teaspoon smoked paprika
• ½ teaspoon ground cumin
• Pinch cayenne pepper, optional
• 1 (28-ounce) can crushed tomatoes
• 2 tablespoons harissa paste*, see note
• 1 cup fresh spinach, chopped
• 3 to 5 large eggs
• ⅓ cup crumbled feta cheese
• ¼ cup fresh parsley leaves
• 1 avocado, sliced