Cook the eggs in gently boiling water for 10 to 12 minutes to hard-boil them.
While the eggs are cooking, heat the vegetable oil in a large non-stick frying pan. Add the onions and cook over a medium-low heat, stirring often, until very soft – about 10 minutes. Add a splash of boiling water if necessary to stop them from sticking.
Add the tomatoes and paprika to the onions, and cook for another 5 to 8 minutes. Season with a little black pepper.
Shell the eggs and cut each into 4. Toast the bread, then top each slice with a quarter of the tomato mixture and 4 egg quarters. Sprinkle with extra paprika or black pepper, if you like.