Add the rice, stock, butter, garlic, onion, salt and pepper. If using an electric pressure cooker, cook on high pressure for 12 minutes with a natural release or if using an instant pot cook on rice setting, cook times should be the same or very similar. When you open the pot the onion and garlic should be relatively close to the surface, remove them the best you can then fluff the rice and serve. If you by chance still have a little extra liquid in your pot. Set on the browning or sauté setting and let the liquid evaporate for a minute or 2.