When sautéing beef, you want to choose thin cuts to allow the meat to cook through over the high heat. Thicker cuts may not cook all the way through, leaving the middle pink (or red).
To create a good sear, let the steaks cook without moving them around in the hot pan, unless it’s to turn them over. Don’t crowd meat in a pan when cooking on the stovetop; instead leave 1/4 to 1/2 inch between each piece in the pan. Crowding the meat can cause it to steam and turn gray.
Always let steaks and other meats rest 5 to 10 minutes after cooking, covered, to allow juices to distribute evenly.
The doneness of steaks is defined by the meat’s interior color. Rare meat is bright red and juicy. Medium meat has a light pink center with light brown edges. Well-done (not recommended) is brown-gray and dry throughout. Check for doneness with a meat thermometer.