01 -
Rough chop the onion, cube the potatoes into medium chunks, cut celery into thin slices, and if using fresh corn, remove the kernels from the cob.
02 -
Switch on 'Saute' mode on your Instant Pot. Melt the butter, then cook onions for about 2 minutes. Stir in the celery and keep cooking for another 2 minutes while stirring and scraping any stuck bits at the bottom.
03 -
Set aside 1/4 cup of the vegetable stock. Toss the rest of the stock, potatoes, and corn into the pot. Cook everything on High Pressure for 5 minutes. Let it naturally release steam for another 10 minutes after that.
04 -
Turn 'Saute' back on. Combine the cornstarch with the reserved stock and pour it into the pot, adding thyme and salt while stirring. Cook for 2-3 minutes, until it thickens.
05 -
If you like, use an immersion blender to create a smoother texture. Mix in the cream and milk, then give it all a good stir before serving.