Press Sauté to pre-heat the Instant Pot. When "hot" appears on the display, add the vegetable oil. Add in the potatoes, garlic, and rosemary. Roll the potatoes around, browning the outside on all sides (roughly 8-10 minutes). With a sharp knife, pierce the middle of each potato (do not stir the potatoes anymore). Pour in the stock. Close and lock the lid of the Instant Pot. Press Manual and adjust time to 11 minutes pressure cooking. When time is up, release pressure and open the Instant Pot using quick release method. Remove the outer skin of the garlic cloves and serve the garlic whole or smashed with the potatoes. Sprinkle everything with salt and pepper to taste. Enjoy!