Pat the tenderloins dry and rub with salt, pepper, and garlic powder. Sear in a hot skillet with the olive oil for 2 to 3 minutes per side, until browned on all sides — this happens on the stovetop, not in the crock pot, and it's where most of the flavor in this recipe actually comes from.
Whisk together the broth, mustard, honey, and minced garlic in a small bowl.
Place the seared tenderloins in the slow cooker, tuck the herb sprigs alongside, and pour the broth mixture around — not over — the meat.
Cover and cook on LOW for 2 1/2 to 3 hours. Start checking the internal temperature around the 2-hour mark.
Pull the pork at 145°F to 150°F; it will climb a few more degrees while it rests.
Remove the pork and tent loosely with foil. Rest 10 minutes before slicing — this is what keeps the juices in the meat instead of on the cutting board.
Pour the liquid from the slow cooker into a small saucepan and simmer for a few minutes to thicken slightly, then spoon it over the sliced pork.
Notes
Important: Always check the internal temperature of the pork loin—it should reach 145°F for safe, juicy doneness. Overcooking can dry it out.