I wandered into Gourmet Glatt and asked Reb Yehoshua, who runs the meat department, which cut of meat he recommends for Philly steak sandwiches. He steered me to the large kolichel, which doesn’t have the connective tissue a small kolichel has and is actually a tender cut of chuck. He partially froze the meat, then sliced it on his industrial meat slicer, and also gave me some tips, since, as it turns out, he grew up in Philadelphia and knows the ins and outs of this classic sandwich. This is my interpretation, with a bit of a more formal twist.