Cut a lengthwise slit in the pork tenderloin, not all the way through.
2 lbs pork tenderloin
Mix olive oil, garlic, salt, and Italian seasoning in a bowl. Coat the tenderloin and marinate for 15 minutes.
1/4 cup olive oil, 3 cloves garlic, 2 tsp salt, 2 Tsp italian seasoning, 1/2 tsp pepper
Place the tenderloin on a grill over medium heat, slit side up. Add garlic and remaining marinade to the slit. Grill for 10 minutes.
Turn over the tenderloin and grill for an additional 5 minutes. During this time, spread the pesto butter on top of the tenderloin. Keep grilling until the internal temperature reaches 145°F. This will likely take 5 more minutes. Allow it to rest for 5 minutes before slicing.
2 tbsp of pesto butter