In its most basic form, corn chowder includes bacon, onions, potatoes, corn and either milk or cream. It is typically thickened with a roux (flour cooked in a bit of fat—in this case bacon fat and butter). The recipe that I turn to most often is from The New Basics Cookbook. I make it almost exactly as written, only omitting a final garnish of sautéed red pepper (a widely popular addition) and sliced green onions. There is nothing wrong with this garnish—corn and peppers are a great combination—I have just been in the habit of leaving them out.
When you make the soup, make sure that you cook the bacon until it is almost crisp—it will continue to render a bit after the onions are added, but not too much. If the bacon isn't sufficiently rendered, you will have flabby pieces of fatty bacon floating around your soup. Also, make sure you take the time to cook the onions until they are very tender before adding the flour and proceeding with the rest of the recipe. Crunchy bits of onion are unpleasant in a soup full of soft textures.
As you work through the recipe, you'll notice that there is an addition of butter before the onions are added to the pan. If the bacon is very fatty, this butter may not be necessary. On the occasion when the bacon does give off a lot of fat, I add the onions to the bacon and only add butter if the pan appears to be dry. There should be enough fat in the pan so that the onions are gently sizzling in the fat. If they aren't, add some or all of the butter. Before adding the flour, check the pan again to see if more fat is needed. If the onions have absorbed all of the fat, or the bacon was very lean, then you may need to add more butter. There should be enough fat in the pan to form a paste with the flour.
A couple of years ago, when the weather began to cool off and I was in the mood for corn chowder, I had some of the first sweet potatoes of the season in my pantry. I also found that I was short on Idaho potatoes. Not wanting to run to the store, I thought I would substitute sweet potatoes for some of the Idaho potatoes. We loved the resulting "Corn & Sweet Potato Chowder". I almost always make it this way now. It's perfect for this time of year. What surprises me today is that I had never thought of this combination before. Sweet potatoes are great with bacon. Furthermore, I am particularly fond of corn paired with sweet potatoes (or winter squash)....something about the sweetness of these two vegetables together pushes my taste buttons. And if you still have some sage left in your garden (it usually hangs on for a while), try adding some to the onions and bacon as they cook. It makes a nice accent to the sweet and salty flavors of this autumn variation on traditional corn chowder.