Save yourself some time and tears and let the grocery store do some of the work for you. Many stores now sell chopped onion in the produce section. This recipe was written by the Healthline Editorial Team: http://www.healthline.com/health-recipes/sweet-potato-and-roasted-red-pepper-soup —Healthline
Place sweet potatoes on a microwave-safe plate wrapped in plastic wrap. Poke a few holes in the plastic--not the potatoes. Microwave on high 6 minutes. Turn potatoes over and microwave another 6 minutes or until a knife pierces potatoes easily. Let cool 5 minutes.
Combine onion and 1/2 cup broth in a large saucepan. Bring mixture to a simmer and cook until onion is tender. Pour mixture into a food processor or large blender and puree until smooth. Add red pepper and process until smooth. Pour mixture in saucepan.
When potatoes are cool enough to handle, scoop the flesh out of skins and place in food processor. Process, adding broth and enough water until smooth. Add to saucepan with red pepper mixture. Bring to simmer, adding broth until desired consistency is achieved. Add lime juice and soy sauce and simmer 2 minutes. Season to taste with salt and pepper. Add top with sour cream.