1. In medium cast-iron pan or shallow saucepan with lid, heat vegetable oil over medium-high heat. Add sausage and break into pieces. Stir frequently until well browned and transfer to paper towel-lined plate, leaving oil in pan.
2. Add onions, bell peppers and serranos, and reduce heat to medium-low. Sauté until vegetables are softened. Add garlic and cook for additional 2 minutes. Add paprika and cumin powder and stir to combine. Season with salt and pepper.
3. Add crushed tomatoes and simmer until slightly thickened. Make 4 wells in tomato mixture and gently crack eggs into them. Cover with lid and cook until egg whites are set but yolks are still runny.
4. Garnish with feta cheese, followed by parsley leaves. Serve with bread.