For homemade tomato sauce, there are no special equipment needed (although a blender is a huge convenience) and you only need to know the most basic of cooking skills. The not so good news is that because tomatoes are not created equal — some may appear more orange than red — your tomato sauce may not have the attractive bright red color that you have come to love after years (maybe, decades even) of using commercial tomato sauce. There is a solution and it is not artificial food color. By adding paprika (made from dried bell peppers), you not only make your tomato sauce redder but you also make the flavors richer.
Boil plenty of water in a pot. When the water is boiling briskly, add the tomatoes (see notes after the recipe).
Cook in boiling water until the skins burst, about one to two minutes depending on the ripeness of your tomatoes.
Cool the tomatoes a bit and peel off the skins.
Place the skinless tomatoes in the blender (or use an immersion blender) and process to your desired chunkiness (you may also do this by hand; I prefer the blender because I don’t lose any of the juices that way).
Heat the olive oil in a pan or pot.
Over medium low heat, saute the chopped onion until translucent (you want the onion to sweat rather than brown so keep the heat down).
Crush and peel the garlic.
Add the garlic and oregano to the onion. Cook, stirring, for about a minute.
Pour in the pureed tomatoes.
Season with salt and pepper. Stir.
Add a bit of sugar to cut down the acidity of the tomatoes.
If the tomato sauce doesn't look as red as you want it, add paprika now — half a teaspoonful at a time until you're happy with the color.
Lower the heat, cover and simmer for 15 to 20 minutes.
And you have your homemade tomato sauce.
Notes
To make peeling the tomatoes easier, you may want to make shallow criss-cross cuts on top of the tomatoes before dropping into the hot water.