
Divide the thinly sliced prime rib onto the Italian rolls. If you want a warmer sandwich, you can heat the prime rib in a lightly oiled pan for a minute or so beforehand.
Top with shredded cheese.
Set into a toaster oven and toast until the cheese is nicely melted, about 4 minutes or so. Remove from heat.
In a bowl, whisk together sour cream, horseradish, mustard and vinegar. Adjust with salt and pepper.
Pour over the melted cheese, then top with sliced roasted jalapeno peppers.
Serve!