To prepare the leeks, slice the tops and bottom root end off and discard. You'll just use the white and light green parts, which look like an enormous green onion. Slice each in half (length-wise) and then in half again. Chop fine. You need to wash them thoroughly. I like using my large OXO Salad Spinner for this. I dump the chopped leeks into the liner bowl that is resting inside the clear plastic bowl and then fill completely with cold water. Let it sit for 1-2 minutes to let the dirt and sediment sink to the bottom. Lift out the salad spinner liner, then dump the dirty water in the sink. I repeat this process 3 times to be sure they are clean.

Heat the butter and olive oil in a soup pot over medium-high heat. Once melted, add the leeks and saute, stirring occasionally for about 5-7 minutes.

Meanwhile, peel the potatoes and chop into about 1-inch pieces. Add the potatoes, chicken broth and about 1 teaspoon of salt to the pot and bring everything to a boil. Reduce heat and allow to simmer for about 15 minutes. Add the broccoli and continue to simmer for about another 10 minutes until both the potatoes and broccoli are very tender.

Remove the soup from the heat. If you have a stick blender, blend the soup until it's very smooth. Or, put the soup in a food processor and puree until smooth. Taste, add salt if needed. Serve topped with toasted pine nuts.