In the meantime, heat 3 tablespoon of butter in an oven-safe pan over medium heat. Add the potatoes, onion, jalapeño, and season with salt and pepper. Mix well and transfer to the oven. Cook 15 minutes. Remove from the oven.
Create little wells in the potatoes for the eggs. Drop an egg in each well. Return back to the oven. Cook ~7 minutes until the whites are cooked, but the yolks are still runny.
Garnish with freshly chopped parsley and some salt and pepper.