Mix all the ingredients for stuffing, use the oil only to combine the ingredients, so drizzle a little at a time, just to wet the other ingredients so they mix well. (The thyme and sage is what brings out the pork in this dish, so add it to taste how you like. When you add it make sure you taste or smell the thyme and sage, but do not over do it, those two spices are strong. Use more thyme than sage.)
Rinse pork butt, then make small slits all over for stuffing the herb mixture into. After stuffing the pork roast, sprinkle salt, old bay seasoning, meat tenderizer and Applewood rub all over, then moisten hands with oil and rub those spices all over.
Place in roasting bag then put sliced onions all over it. Seal bag (don't forget to poke smalls holds in the bag) and bake at 350 degrees for 3 1/2 to 4 hours. Let settle for 10-15 minutes, then cut and serve. Also makes a juice for sauce or gravy that can be used over rice or potatoes.