To prepare the smoky roma tomato sauce, heat oil in a medium saucepan over medium heat. Add the onion and garlic, sautée stirring regularly for 2-3 minutes until softened. Add Mutti Baby Roma Tomatoes, sherry vinegar and paprika; bring to the boil. Turn down heat to a simmer, cover and cook for another 5 minutes. Remove lid and cook for a further 2 minutes, or until reduced to a sauce. Season with salt and pepper to taste. Keep warm.
Meanwhile to prepare the fried capers, heat oil in a small saucepan over medium heat. Fry capers in batches, until they pop and uncurl. Use a slotted spoon to remove and drain capers on kitchen towel. As they cool, capers will become crunchy.
Place the flour and smoked paprika in a medium bowl. Add salt and mix well. Coat sardines in flour mix, shaking off excess and place on a tray.
Heat half of the oil and butter in a large heavy based frying pan over medium heat. Cook half of the sardines, starting skin side down, for 1 minute on each side, or until just cooked through.
Serve sardines with hot buttered sourdough toast, smoky roma tomato sauce, fried egg and sprinkled with fried capers.