2 pork tenderloins, trimmed of fat (about 2–2 1/2 lbs.)
2 T kosher salt
2 C warm water
1 T apple cider vinegar
1 T brown sugar
1/2 C ice cubes
2 T lemon juice
3 T butter sliced into 6 pats
Spice Mix:
1 T EACH chili powder, garlic powder
1 t EACH salt, onion powder
1/2 t smoked paprika
1/4 t pepper
Herbs to add LATER:
1/2 t EACH dried parsley, dried basil, dried oregano
Optional to make gravy:
1-2 t cornstarch with 1 T water
Preheat oven to 400 degrees F. Lay two long pieces of foil on a baking sheet – these will be used to fold up each tenderloin separately. Or use a skillet with a lid.
In a 4-C measure, mix salt with warm water until dissolved. Whisk in apple cider vinegar, brown sugar and ice. Transfer to a gallon-size freezer bag, and add the pieces of pork. Brine for exactly 20 minutes then remove pork from brine. (The pork can become mealy if left in the brine any longer.)
Meanwhile, combine all of the Spice Mix ingredients (not the "Add Later Herbs") in a small bowl.
RINSE pork and pat very dry. (Discard baggie and brine.) Evenly rub pork all over with spice mix.
Heat 1 tablespoon vegetable oil in a large skillet over medium high heat. When oil is very hot and just smoking, add pork tenderloins, you may need to work in batches. Sear each side of pork until golden, then transfer to foil or leave in skillet if using the skillet for baking.
Evenly sprinkle tops of pork tenderloins with remaining herbs (parsley, basil, oregano, thyme) then rub into pork.
Evenly drizzle each pork tenderloin with one tablespoon of lemon juice (2 tablespoons total), then top each tenderloin with 3 pats of butter. Bring up the sides of the foil to completely enclose each tenderloin. Or place cover on the skillet.
Bake at 400 degrees F until pork registers between 145- and 150-degrees F (63 and 65 degrees C) at the thickest part of the tenderloin, 15-25 minutes depending on thickness. This means the pork will be juicy and slightly pink in the middle. To check the temperature, carefully unwrap the foil, then wrap it back up if it needs to continue baking.
When pork is done, loosen foil or open lid slightly (so steam can escape) and let stand 5-10 minutes before slicing. Season with additional salt and pepper to taste and serve with accumulated butter sauce in the bottom of the foil.
Optionally, you can make a gravy with the liquid instead. Pour into a small saucepan and heat. Mix cornstarch with water and add to the hot liquid. Stir until thickened.
