1Brine for Tenderloins:
For 2 tenderloins, in a medium bowl mix kosher salt and sugar with cool water until dissolved.
Trim the tenderloins of excess fat and silver skin.
Submerge them in the brine and let stand for 45 minutes.
After 45 minutes, remove the pork from the brine, rinse thoroughly and pat dry.
In a small saucepan, bring the OJ concentrate, brown sugar and rosemary to a simmer.
Simmer until the mixture reduces to about 2 tablespoons.
Set aside and cool slightly.
3Orange Balsamic Sauce:
Heat the oil in a small saucepan over medium heat.
Add garlic and rosemary and cook until fragrant and sizzling (about 30 seconds).
Stir in marmalade and vinegar.
Heat until warm.
**NOTE** After slicing the pork, add any juices from the carving board to the sauce before serving. Pass separately when serving the pork tenderloin.
Rub the brined tenderloins all over with the glaze and then season with pepper.
Heat gas grill, turning all the burners to high until fully heated, 10-15 minutes.
Put the pork on the hot grill grate. Close the lid and grill for 7 minutes.
Turn pork over, close lid and grill another 6 minutes.
Turn off the heat (keep the lid closed) and continue to cook for another 5 minutes on the residual heat.
At this point, an instant read thermometer inserted in the middle of the thickest end of the tenderloin should read 145-150 degrees. If not, close the lid and let the pork continue to roast in the residual grill heat.
Remove pork from the grill and let rest for 5 minutes before carving.
Cut across the grain into 1/2 inch slices and serve immediately.