Bring the water, milk, and salt to a boil. Slowly whisk in Polenta, turn heat to low and continue whisking for 5 minutes, or until Polenta is smooth and creamy. Remove from heat and spread into 1" think layer pan to cool.
Place olive oil, onion and garlic in a sauce pan on medium high heat. Add tomatoes and leave on the heat to let it reduce. Once the sauce has thickened add spinach and leave on very low heat. Cut out circles of the cooled Polenta using a 4" round cutter. In a separate skillet, add 1 tablespoon olive oil, and heat over medium heat. Fry the circles of polenta until crispy. Then remove from pan, and in the same skillet, fry all four eggs separately with one pat of butter until the yolk is set but runny.
To assemble, cover the Polenta with desired amount of sauce, and top with the fried egg sunny side up.