Substances:
- 1 2-lb. pork tenderloin, trimmed of sinew and excess plump, and tied with kitchen cord
- ¼ cup canola oil
- 3 tbsp. finely chopped rosemary
- 3 dapper cloves garlic, peeled and finely chopped
- Kosher salt and freshly ground dim pepper, to taste
- 2 tbsp. unsalted butter
