Tomatoes

Probably the most common vegetable in the U.S., tomatoes are actually a fruit rather than a vegetable and they are native to the Americas.  It is unclear if the Aztecs actually ate the red tomato we are familiar with today or if the early references were to the green tomatillo.  Today there are hundreds of varieties from long, plump San Marzano to the giant beef-steak varieties down to tiny cherry and grape sized tomatoes.  In the past few years heirloom varieties have become abundant in grocery stores and farmer's markets. 

Sadly, most grocery store varieties are specially bred with thick skins for machine harvesting and are picked green and never develop that distinctive tomato flavor.  When possible buy from local growers or grow your own.  If you have a freezer, whole ripe tomatoes can be popped into zip lock bags and frozen whole. Although the thawed tomatoes can be sliced and used like a fresh tomato they are perfect for use in soups, stews or sauces.

Substitute For Tomatoes

If you don't have fresh tomatoes then here are some good substitutes:

• For 2 cups chopped tomatoes needed you can use 1 16oz can of whole or chopped tomatoes.  Not only are canned tomatoes a good alternative they are frequently better than fresh "grocery store" tomatoes.  This is because tomatoes grown for canning are allowed to ripen on the vine to develop their full flavor.  Tomatoes to be sold fresh are no vine-ripened and tend to lack all the characteristics of a fresh, fully-ripened tomato.
• OR - For 1 lb of fresh tomatoes needed, slice 6-8 sun-dried tomatoes.  Once cooked into a sauce, soup, or stew, you'll get a very rich tomato flavor. 
• OR - For a different flavor profile you can substitute tomatillos which provide a tart flavor.  Tomatillos work well in many Mexican recipes.
• OR - Use different types of tomatoes interchangeably.  For example, you can use cherry tomatoes to replace salad tomatoes.  Plum tomatoes or San Marzano tomatoes are drier and meatier and can be used in salads but are best for sauces or soups.  You can use salad tomatoes for making tomato sauce but the sauce will be sweeter and thinner.