I learned a lot of my cooking methods from my father, who was far more about intuition and going by scent and taste rather than strictly following a recipe. He also taught me that you might as well share "secret" recipes, since skill and equipment are going to matter more than precise ingredients. Get a dozen people to make the same hollandaise sauce and you're going to get twelve very different results.
But I've had a few requests for this one, and I might as well share it here. I'm not the first to make sweet potato soup, but this is the way I do it and my dining companions are always happy with it.
Benito's Sweet Potato Soup
Makes roughly four litres/a gallon
5 large sweet potatoes
1 large yellow onion
5 cloves of garlic
a knob of ginger
1L or qt. of chicken broth
half a bottle of white wine
2 apples (Golden Delicious or Granny Smith)
Start by roasting the sweet potatoes in the oven until soft. They don't have to be fully baked, just enough to get the skins off easily. About an hour after you put them in the oven, dice the onion and begin sautéing it in an enameled cast iron pot or stock pot. Before the onions brown, add the minced garlic and ginger, being careful to keep either from burning.
Next, peel and dice the apples. Add to the pot and continue stirring over medium heat. When caramelization first starts happening, add in the wine and chicken broth and bring to a slow simmer.
By this point the sweet potatoes should be cooked enough and you can remove them from the oven. Peel carefully so as not to get burned and roughly chop the tubers. Add to the pot and allow to slow simmer for an hour with the lid on. Don't let it boil, and it can go like this for two or three hours if desired. About thirty minutes before serving, hit it with a stick blender and blend until it's the consistency of baby food. Turn the heat on its lowest setting and stir occasionally to keep it mixed well.
For garnish, I usually grate some nutmeg on top, and do a little design with thinned sour cream. Do a few lines in a row and then drag a knife through them like I did, or you can do a simple spiral or a spider web or all kinds of other cool things like my goofy "square root vegetable soup" idea. If you screw up, just stir the cream into the soup and start over. Nobody will know the difference. Sometimes I top with a few chopped scallions.
As for other variations, depending on my mood I either add Southwestern seasonings that involve smoked chiles, or an Indian garam masala flavor, or even Chinese five spice powder when I'm in the mood. You can adjust this quite a bit to either fit your mood or what you're serving during the following courses.
It's a simple sweet potato soup, but it's made a lot of people happy and I'm glad to be able to share it with my readers.