Place an oven-safe rack inside a foil lined rimmed baking sheet. Brush rack with a little olive oil to prevent sticking. Set aside. (recipe note #2)
From left to right, lay bacon strips on a work surface side by side so that they overlap slightly. (The finished width should be wide enough to span the full length of the pork tenderloin.)
Place pork tenderloin on a clean plate and tuck thin end under to create an even thickness.
In a small bowl, stir olive oil, rosemary, garlic, salt and pepper until well combined. Spoon mixture over pork and rub all over to coat.
Place seasoned pork tenderloin on the center of the bacon so that it spans all of the slices. Starting from the front edge of the right, topmost bacon strip, wrap one strip at a time over the top of the tenderloin. Repeat with the back edge of each bacon strip, again working right to left, so that the bacon strips wrap the tenderloin completely.
Carefully place the pork tenderloin wrapped in bacon seam side down on the prepared rack inside the baking sheet. Roast for 25 to 30 minutes or until the bacon is crispy and the thickest part of the tenderloin reads at least 145˚F on an instant read thermometer. (recipe note #3) Remove from oven and let stand 5 minutes. Cut into thick slices and serve.
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Notes
If your bacon strips are narrow, you may need 10 or more strips to span the full length of the pork tenderloin.
If you don't have an oven-safe rack, bake directly on a foil lined, rimmed baking sheet.
For extra crispy bacon, flip on the broiler for 1 to 2 minutes just before removing pork from the oven.