Preheat oven to 400ºF.
On a baking sheet, place the 2 tenderloins side by side. Cut a slit lengthwise down the middle of each tenderloin to butterfly and open them up. Season the insides with salt, pepper and rosemary, then close them up, tucking skinny ends underneath.
Season the outside of the meat with salt and pepper. Lay overlapping slices of pancetta over the tenderloin like shingles, until the entire tenderloin is covered. Repeat on the second tenderloin then drizzle with EVOO.