Homemade mayonnaise is very easy to do; you will need only egg, oil, lemon juice, and salt. A few extra ingredients can transform a basic mayonnaise into a very special sauce.
A hand held blender makes this task very easy, as you can use it in smaller containers and prepare only the amount you need. The only trick to get the mayonnaise to thicken is to have all ingredients at the same temperature, that is room temperature.
Prepared tomato sauce is really convenient. The problem most of them come seasoned with Italian herbs, great for pasta dishes, but not suited to other dishes -basil is not our favorite herb for fish, as an example. This home made basic tomato sauce can become Italian, by adding basil and oregano; French cuisine, by adding herbs the Provence and capers; good for game, by adding thyme and rosemary; good for fish, adding bay leaf and white wine.
Tzatziki, a very simple sauce, is a great accompaniment to traditional Greek. Tzatziki can also be used as dip and not only in traditional Greek cooking, try it as filling for baked potatoes or served with fish fingers instead of tartar sauce.