Cut artichoke in half.Take a pairing knife and carve around thistle then take a spoon and scoop out the thistle part. Put face down in pressure cooker. Once the cooker starts to vent put timer on for 15 minutes. After the timer goes off I then take the pot and run cold water over it to stop the cooking process. Use a flexible spatula to remove the chokes. They are will fall apart easily so that is why I use a spatula to plate them. My favorite way to eat them is with mayonnaise.