Trim away and discard any excess fat and silver skin from the pork loin. Combine the salt, pepper and herbes de Provence and rub over all sides of the meat; use all of the spice mix.
I like to tie the pork loin every couple inched with butcher's twine so that the roast holds it's shape, but that is totally optional.
At this point the pork loin is ready to grill, but I like to let it sit, lightly covered with plastic wrap, in the refrigerator for a few hours to as long as a couple days for a deeper seasoning of the meat. Remove from the refrigerator 45 minutes before grilling.
Add the blackberries, mustard, and jam to the bowl of a blender and puree. Scrape into a small saucepan and simmer for 5 minutes. Remove from heat and set aside until needed.
Set up grill with two zones for direct and indirect cooking with medium-high heat. Brush and oil the grates before cooking.
Place pork on the direct heat side of the grill and sear the meat for about 5 minutes per side or until marked. Transfer to the indirect side of the grill and close the grill cover. Cook for another 15 to 25 minutes or until the internal temperature reaches 140°F (no more than 160°F, if you like you pork well-done). Brush with Blackberry Mustard Sauce and move to the direct side of the grill, sauce-side down. Cook for a minute or two, brush with more sauce and flip. Repeat this a couple times to caramelize the sauce (layers of flavor, baby!). Transfer the pork to a cutting board and tent with foil for 10 minutes before slicing.
Brush pork loin with more sauce and slice. Serve with extra sauce on the side.
Recipe by Grilling Outdoor Recipes powered by Bull Outdoor Products at http://www.grillingoutdoorrecipes.com/blackberry-mustard-glazed-pork-loin/