HOW TO MAKE HEARTY BROTHS
Hearty broth is simply a clear broth but with more intense flavor and texture. Often, pasta or meats are added to a hearty broth to give it more full body. Also, some ingredients, either a vegetable, meat or fish, can be used as a predominant flavor in a hearty broth (e.g. onion soup) and they are cooked directly in the broth which is then served as is. For this reason, hearty broths are not clear broths, and they should have a rich color if you use the ingredients that ought to give good color.
What do you choose for a hearty broth? It is normal to choose one or a few of very aromatic vegetables and make them the main flavor-generating ingredient in the soup. Also some meat or fish can be used, although it is not that common. Of course, if the single vegetable doesn't provide enough flavor or enough interesting flavor on its own then other ingredients are added to the soup.
In any case, the ingredients used for the broth are just cooked until tender, and then the broth is served. One can also remove the cooked vegetable while continuing to work on the flavor of the soup, and then put the vegetables back to the soup and serve it. The easiest way of course is to make it all in one step. However, some ingredients like the starchy beans or pasta are normally cooked on their own and then they are added to the broth. Whatever the choice, the general rule is to cook the soup without compromising the quality of the ingredients and the final result - avoid overcooking the veggies and meat and you'll be fine.
For the soup you will also need a prepared stock or broth wherein you can cook the aromatic vegetable or meat. The easiest way to work on the hearty broth is to slowly heat up the stock to simmering while preparing the fresh vegetables or meat. They should all be trimmed and cut into even and fairly small pieces, since you usually only need to cook them for a short while in the pre-made stock. Simmering and relatively fast cooking of the fresh ingredients will not destroy the flavor of the stock.
To garnish a hearty broth you can use a lot of things - cheese, herbs, eggs, croutons, and pureed aromatic or spicy vegetables are common in use. You should also season the broth accordingly. For example, if you make a tomato soup, it is nice to add some red wine vinegar and perhaps a red chili pepper purée.
For 1 liter/1 quart of hearty broth you'll need:
1 lb/500 g of the main aromatic ingredient, like pasta, one or two vegetables, meat, fish, etc.
1.2 liter/1.2 quart of a pre-made stock or broth
seasoning that fits the main ingredient in the soup, as well as the classic salt and pepper, and perhaps bouquet garni
To make a hearty broth do the following:
1. Start by bringing the pre-made stock to simmering and meanwhile prepare the main ingredient(s) of the broth by trimming it and cutting into small pieces. It is common to lightly sauté or brown the vegetables or meat in some oil in a separate pan as a part of preparation - this will create some additional flavor.
2. Add the chosen ingredients to the simmering stock and cook until tender. Adjust seasoning at the end of the cooking. Remember that some ingredients will cook for quite a long time in a simmering broth but the flavor will also be best with slow cooking.
3. Serve the soup as is, when the ingredients are tender and when the flavor is satisfactory.