In your Instant Pot, add the pork tongues, chicken stock, and peppercorns. Cook for 40 minutes on high. If you don't have a pressure cooker, the tongues can be boiled on the stove top for about 2 hours.
Once done, let the tongues rest until they are completely cooled off. Peel the skin from the outside of the tongue. Slice into 1/4" thick pieces. Save 1 cup of the tongue broth.
In a large sauté pan, melt the butter over medium high heat. Add in the onions and garlic. Cook for 3-4 minutes.
Add in the tongue slices and soy sauce. Cook for 2 minutes a side.
Stir in the corn. Cook for another 2 minutes.
Add in the evaporated milk and tongue broth. Season with salt and pepper. Simmer for 7 mutes, or until the milk thickens.
Stir in the heavy cream. Simmer for another 5 minutes.
Serve over steamed rice.