Sweet Potato Soup with Sausage and Collard Greens Recipe

I made this soup a few weeks ago with chicken and sun dried tomato sausage and really loved it. I remade it on Halloween night with Linguica, and didn't love it as much, but it was still pretty good.

Sweet Potato Soup with Sausage and Collard Greens

2 lb. Sweet Potatoes, quartered lengthwise and sliced
1 lb Potatoes, 1/2 inch dice
12 oz. Precooked Sausage (Your choice)
2 tsp Olive Oil
1 Onion
2 Cloves Garlic
6 Cups Chicken or Veggie Broth
1 Bunch Collard Greens
Red Pepper Flakes to Taste (Depending on heat of the sausage you choose)

Slice sausage into 1/2 inch rounds. Brown in olive oil over medium heat until browned on both sides, about 10 minutes. Remove from pot and drain on paper towels. Add diced onions to pot and cook for about 10 minutes. Add garlic, diced sweet potatoes and potatoes, stir to coat. Add broth and bring to a boil. Let boil about 20 minutes, then add in roughly chopped collard greens and let simmer for about 10 minutes. Add sausage back into the pot and let cook for about 15 minutes, or longer.