Select the SAUTÉ setting on the Instant Pot and heat 2. 0 tbsp. (1. 0 oz / 30g) of olive oil.
Add 2. 0 tbsp. (1. 0 oz / 28g) of butter and melt it.
Add the 1. 5 lbs. (24. 0 oz / 680g) of halved potatoes and sauté, stirring occasionally, for 10 minutes until the flat halves have turned a beautiful golden brown.
Season the potatoes with 1. 0 tsp. (0. 2 oz / 6g) of sea salt and 1. 0 tsp. (0. 1 oz / 2g) of ground black pepper, stirring well to ensure even coating.
Pour in 0. 5 cups (4. 0 oz / 120g) of water or broth to deglaze the pot. Close and securely lock the lid.
Press the CANCEL button to reset the cooking program, then press the MANUAL button and set the cooking time for 6 minutes at HIGH pressure.
Once the cooking cycle is complete, select CANCEL again and let the pressure Naturally Release for exactly 20 minutes. Release any remaining steam manually, then carefully uncover the pot.
Taste your crispy potatoes for seasoning, adding an additional 0. 1 tsp. (0. 02 oz / 0. 6g) of salt if desired.
Serve immediately while warm.
Dry Before You Fry: Ensure your potato halves are completely dry before adding them to the hot oil and butter. Surface moisture creates steam, which is the enemy of getting a perfectly golden crust!
Don't Overcrowd the Pot: For the ultimate Crispy Potatoes, make sure the flat sides are touching the bottom of the Instant Pot in a single layer during the sauté phase. If you have a smaller 3-quart model, you may want to brown them in two quick batches.
Let Them Breathe: After the natural pressure release and uncovering the pot, let the potatoes sit for just a minute or two before serving. The rapidly evaporating surface steam will help firm up the exterior even more.