Fry the sliced onion and minced garlic in a splash of olive oil in a large frying pan for about 10 minutes, or until the onion is softened but not browned.
Add the tomato passata and basil and simmer for another five minutes or so. Season with dried chilli flakes, salt and pepper to taste.
Spoon the tomato sauce mixture into four ramekins or small oven-proof bowls, dividing the mixture evenly. Crack one egg into each ramekin/bowl.
Place the ramekins/heat-proof bowls on an oven tray and bake them in the oven for between 15-20 minutes. Start checking the eggs regularly after 15 minutes have passed. Ideally, take them out of the oven when the egg whites have set slightly but the yolks are still runny.
To finish, place the ramekins/heat-proof bowls under a hot grill for approximately 2 minutes to brown the tops.
Recipe by The Cat's Pyjamas at http://www.thecatspjsblog.com/2013/02/03/baked-breakfast-eggs-in-tomato-sauce-recipe/