Spanish Sofrito
from http://www.tapasbonitas.com/

In every culture the kitchen has its own basic sauces that are made in advance and which are then used in the preparation of a number of dishes. In the Spanish kitchen there are the Sofritos.

1 pound Onion*, chopped
2 pounds Ripe Tomatoes**, skin removed, diced
half a head Garlic, chopped
200 ml Olive Oil, for frying, so not Extra Virgin
1 teaspoon Sugar
1 teaspoon Seasalt

* Spanish cooks like to use the Cebolla Dulce Violeta de Figueres. This is a mild onion, solid, fresh taste, slightly sweet, little bit bitter. We sometimes take them home with us from a trip in Spain, but once we run out of them we switch to a mix of our "standard" yellow onions and sweet white onions.
** In Spain they like to use the Tomate de Pera. If you can't get any of those, try any tomatos as long as they are mature and intensely red.

Preparation of this fragrant Spanish Sofrito sauce takes some time and attention, but is really quite easy:

Grind the chopped onion to a smooth sauce using a blender or other kitchen tool.

In a sautee pan over slow fire, and while stirring contantly, cook the onion sauce until all internal moisture has evaporated and the sauce has turned into a paste.

Meanwhile, add the garlic to the oil and grind to a smooth emulsion (fine garlic particles in oil) using a blender or other kitchen tool;

Once the internal juices have evaporated from the onion sauce (be careful not to let it burn!) add the garlic emulsion, turn the fire higher, and sautee the mix until it starts to get brown.

During sautéing, add oil if necessary to prevent the mix from burning or sticking to the bottom of the pan.

Turn the fire to slow, add the sugar and salt, keep stirring.

Meanwhile, grind the diced tomatos to a smooth sauce using a blender or other kitchen tool.

Add the tomato sauce to the onion, keep stirring.

On slow fire, and constant stirring, allow most of the tomato juices to evaporate so the sauce thickens.

Once the sofrito sauce has thickened to a nice consistency, take the pan off the fire and allow it to cool down.

Once the sauce has cooled down, distribute it into small portions that can be frozen in small plastic containers or as ice cubes, ready for future use!