Heat olive oil in a large pot over medium heat, add diced onion and sauté for about 5 minutes until translucent.

Add cranberries, brown sugar, cinnamon, and nutmeg to the pot, stirring well to combine. Pour in vegetable broth and bring to a gentle boil for 5–7 minutes.

Reduce heat to low and simmer uncovered for 20 minutes, stirring occasionally.

Remove from heat and use an immersion blender to puree the soup until smooth, adjusting seasoning with salt and pepper.

Ladle into warm bowls and garnish as desired before serving.