Heat 1 tbsp of the olive oil in skillet. Add chopped onion and saute until onion is translucent. Add chopped mushrooms and continue cooking for another 3 to 5 minutes. Season with salt and pepper and stir in oregano and rosemary. Set aside.

Butterfly the pork loin, basically cut the pork down the center, without completely cutting through, so when you open the two halves they resemble a butterfly. Use your meat mallet to flatten it a bit.

Take the mushroom mixture and spread it down the center of the pork loin and bring the 2 sides up. Use butcher strings to tie around the roll at 1 inch intervals.

Season the stuffed pork with salt and pepper and in a large skillet heat the other tbsp of olive oil. Sear the pork loin on all sides. Move the pork loin in a large oven proof pan.

Roast uncovered for about 30 minutes or until done to your preference.

Remove from the oven and wrap it with foil and let it sit for 15 minutes before slicing.