In a large soup pot on medium high heat, add olive oil. Whisk Thai curry paste to oil until aromatic. Add coconut milk, sugar, salt, and vegtable broth, mix well. Add chunks of squash and let the liquid come to a boil.
Reduce heat to low and cover for at least 20 minutes or until a knife runs through the squash easily.
Use an immersion blender, or any blender (careful not to put hot soup in a regular blender, ouch) and blend until smooth. Squeeze in limes.
While warm, add spinach to soup and stir until wilted.
Top with feta (it's a must), cilantro, and zest of lime. Add meat if desired, but surprisingly not needed. I love to have white rice on the bottom of the soup, so you can have some with every bite, and a side salad. Croutons on top would be great too. Enjoy this cozy and hearty fall favorite!