01 -
Roughly chop onion, cut potatoes into medium chunks, slice celery thinly, and cut corn kernels off cob if using fresh corn.
02 -
Set Instant Pot to 'Saute' on Normal. Melt butter, saute onion for 2 minutes, add celery and saute 2 more minutes, scraping any browned bits.
03 -
Reserve 1/4 cup broth, add remaining broth, potatoes, and corn to pot. Pressure cook on High for 5 minutes. Natural release for 10 minutes.
04 -
Turn on Saute. Mix cornstarch with reserved broth and add to pot with salt and thyme. Cook 2-3 minutes until thickened.
05 -
Optional: blend to desired consistency with immersion blender. Add milk and cream, stir to combine, and serve.