Slather one pork tenderloin (1 pound) generously with Dijon mustard.
Take a healthy scoop each of whole coriander seeds and whole black peppercorns and run them through a spice grinder just to break them up and press them onto the pork.
In an oven-proof fry pan (I used my cast iron) brown tenderloin in a small amount of oil until browned on all sides.
Move pan to oven and bake 350 degrees for about 30 minutes