Add onion, celery and salt; stir to coat.
Stir in tomato paste, sage, white pepper and crushed red pepper, if using.
Cook, stirring constantly, until fragrant, about 1 minute.

Photo: Ali Redmond
Add stock, increase heat to high and bring to a simmer.
Once simmering, add peanut butter, whisking until it melts into the stock.
Using an immersion blender or in batches in a blender, process the soup until it is very smooth.
(Use caution when blending hot liquids.)
Serve the soup topped with chopped peanuts and chives (or parsley).
To make ahead
Refrigerate for up to 4 days.
- Daily Values (DVs) are the recommended amounts of nutrients to consume each day.
(-) Information is not currently available for this nutrient.