Whisk together all the marinade ingredients.
Place the tenderloin in a zippy bag with the marinade.
Squish it around for a minute, then refrigerate for a minimum of 1 hour, 3-4 is ideal. Overnight might turn this mushy.
Remove pork from the bag, shake off any excess, and let rest at room temp while the oven preheats to 425F (this works even better on a grill).
Place the pork in a cast iron or similar ovenproof skillet, with the used marinade.
Bottom rack for 10 minutes. Flip and cook another 10 minutes.
Check IT at the thickest part, we want 137-140F. Continue cooking 1-2 minutes per side until desired temp reached.
Broil on the top rack for 1-2 mins to finish.
Transfer to cutting board, and let rest 10 minutes before cutting.
Spoon any leftover sauce from the pan over the pork, and/or potatoes you might be making to go with the pork. The sauce will be very flavourful, so taste it first so you don't overdo it.