Begin by preparing the turkey breast. Pat it dry with paper towels, then rub it all over with olive oil.
In a mixing bowl, combine the salt, pepper, thyme, rosemary, paprika, and Dijon mustard. Rub this mixture all over the turkey breast.
Heat a skillet over medium heat. Add the diced onion and sauté for about 2-3 minutes, until softened. Add minced garlic and continue to sauté for another minute.
Pour the chicken broth into the crockpot. Place the sautéed onions and garlic on the bottom of the crockpot.
Carefully place the seasoned turkey breast into the crockpot on top of the onions and garlic.
Cover the crockpot and set it to low heat. Cook for approximately 6 hours or until the turkey reaches an internal temperature of 165°F (75°C).
Once fully cooked, remove the turkey breast from the crockpot and let it rest for about 10 minutes before slicing.
Serve slices of turkey breast with the juices from the crockpot as a gravy.