Heat cooking fat (ghee or oil) in a large pot to medium heat. Add leeks or shallots and saute for 1-2 minutes. Add garlic and ginger and keep an eye on it so it does not burn. Cook another minute.
Add curry paste, turmeric, and sugar and combine/cook till fragrant. Add sweet potatoes and broth and simmer until the potatoes have softened. Mine took about 15-20 min.
When the potatoes are starting to soften, add in the coconut milk and combine till smooth. Remove the pot from heat and allow to cool for about 10 minutes.
Add soup mixture to blender or food processor (or use a handy dandy immersion blender) and process till smooth. As you do this (if using a blender or food processor), use the same large pot to heat your cooking fat and add your choice of "mix in" vegetables. Stir fry veggies till cooked through, but not too soft. Mine took about 7-8 minutes.
If you're adding chicken, you can cook it in the pan with the veggies or stir fry it in a separate pan to keep a better eye on it. While I'm a fan of one pot dishes, the juices from the chicken will make it more difficult for your veggies to not get soggy. This will also cook around 7 minutes.
Return blended soup mixture to the large pot with your stir fried veggies. If too thin, you can add more stock or water. Cook over low heat for another 10 minutes. Top with pumpkin seeds, cilantro, green onions...whatever you like!