Place washed berries in the bottom of the inner pot. Sprinkle sugar over the berries. Do not stir!
Squeeze the lemon half over the berries and sugar, being careful not to drop any lemon seeds in the pot.
Close and lock the lid, turning the steam release valve to closed. Press Steam and adjust down to 3 minutes. Press Start/Stop.
When the cooking cycle has ended allow a 10 minute natural pressure release. Then, open the steam release valve to release any remaining steam. Press Start/Stop and open the lid.
Stir the berries and liquid. Press Brown/Saute and adjust the temperature to Low. Simmer and stir for 2-3 minutes to cook off some liquid.
Mix the cornstarch and water until smooth to make a slurry. Add it to the pot and continue to simmer and stir for 1 minute or until desired thickness has been reached.
Press Start/Stop and carefully remove the inner pot and set on a cooling to rack to cool.
When it's cool enough to touch, add the jam to jars and store in the refrigerator.