Whisk together the first 6 ingredients. Dip a finger in--do not hesitate to adjust for taste. It should be sweet, but also savory and tangy. It should not be as sweet as a barbeque sauce, for example. If you want a stronger mustard flavor, add more mustard.

Place the trimmed pork tenderloins into a gallon sized Ziploc bag. Scrape the marinade in as well. Press the air out of the bag and seal the bag. Massage the marinade into the pork.

Place the marinating pork into the refrigerator for at least 4 hours and up to overnight.

Preheat the oven to 325 F.

Heat a large, heavy oven-proof skillet over med high heat. When it is hot, add the olive oil. When the oil shimmers, add the tenderloins to the pan. (I like to place a splatter screen over the pan.) Brown the tenderloins on one side, for about 6 minutes.

Flip the tenderloins over and place the pan into the oven. Cook for about 10 minutes, or until the internal temperature reaches 145 F (I let mine accidentally get about 10-15 degrees too high and would have liked them a bit pinker).

Let the tenderloins sit for about 10 minutes out of the oven before slicing.