Heat your cast-iron skillet over medium heat and add the olive oil, listening for a gentle shimmer and slight crackle.
Add the diced onion and chopped bell peppers to the skillet. Cook for about 8 minutes, stirring occasionally until they soften and develop some charred spots, filling the air with a sweet, smoky aroma.
Stir in the minced garlic, cumin, and smoked paprika. Cook for 1 minute until fragrant, ensuring the garlic doesn’t brown too fast to keep that nutty, smoky aroma.
Pour in the crushed tomatoes and stir to combine everything. Let the sauce simmer uncovered for 10–12 minutes, allowing it to thicken and develop a smoky, caramelized scent around the edges.
Season the sauce with salt and pepper to taste, then create four small wells in the sauce using the back of a spoon, spacing them evenly apart.
Gently crack each egg into a small bowl first to avoid shells, then carefully slide them into the wells. Cover the skillet with a lid or plate.
Cook for about 3–4 minutes for runny yolks or 4–5 minutes for firmer yolks, until the whites are set and the eggs have a slight jiggle. You’ll hear a gentle crackle as the whites firm up, and the sauce will bubble around the eggs.
Remove the skillet from heat and sprinkle chopped cilantro or parsley over the top. Add crumbled feta cheese if desired for extra salty creaminess.
Let the shakshuka rest for a minute to let flavors meld, then serve directly from the skillet with warm, crusty bread for dipping and scooping.