In a medium sized sauce pan on medium heat, add in the olive oil. Sauté the onion until translucent and aromatic, about 5-7 minutes.
Add both the whole tomatoes and the tomato sauce, stirring and using a using a potato masher or back of large spoon wooden to break up the tomatoes. Bring the mixture to a boil and reduce to a simmer, allowing excess liquid to boil off and the sauce to thicken, about 10 minutes.
Stir occasionally. Season the sauce with salt and pepper to your taste.Add a dash of red pepper flakes if you like it spicy. Simmer sauce on low while you heat oven to 375 F.
Spoon some of the sauce in a baking sheet. Make sure to not go all the way to the top of the sides. You won't use all of the sauce.
Make small wells in the sauce and gently crack one egg into each well.Carefully add the baking sheet to the oven.
Bake uncovered for 12-15 minutes, until the whites are set and the yolks are still a bit runny.If you like the yolks more cooked, leave in an extra minute or two.
Toss on chopped Italian parsley before serving.