Preheat the oven to 400°F. Rub the pork loins all over with the olive oil and garlic and season generously with salt. Set in a large cast iron skillet and pour the chicken stock around the pork. Roast the pork loins, basting occasionally, for 1 hour.
Remove the pork from the oven and brush all over with ½ cup of the blueberry jam. Return the pork to the oven and roast for 10 to 20 minutes more, or until a meat thermometer inserted in the thickest part of the loin registers 140-145°F.
Remove the skillet from the oven. Transfer the pork to a carving board and loosely cover with foil. Let rest for at least 20 minutes.
Meanwhile, place the skillet on the stovetop and add the remaining TK cup of chicken stock. Cook over moderately-high, scraping up any browned bits on the bottom of the pan. Add the remaining TK cup of jam and cook, stirring occasionally, until you have a pan sauce thick enough to coat the back of a spoon.
Carve the roasts and arrange on a platter. Drizzle with the blueberry-bourbon pan sauce and serve right away!