Clean and peel the russet potatoes, diced into a one inch dice. Set aside
Clean the yukon gold potatoes. Dice into one inch sized dice. Set aside
Clean and dice the onion and celery, mince the garlic.
Turn the Instant Pot on sauté. Allow to heat one minute. Add the olive oil then the diced onion, celery and potatoes. Sauté for two minutes.
Add the garlic, salt and pepper, stir well - saute for another 30 seconds. Add the ham and chicken stock. Stir well. Change the setting to manual.
Add the lid to the Instant Pot and seal. Turn the vent to the seal position. Change setting to steam and set the timer to 11 minutes.
When the timer goes off. Do a quick release by opening the vent valve. Allow all of the steam to release.
When the steam is completely released, remove the lid. Add the cheese and half and half. Using a potato masher, mash the potatoes until they are the consistency you desire.
Check the seasoning. You may need to add an additional ½ teaspoon of salt. Add Tabasco sauce if desired. Stir again, serve and enjoy!