Preheat the oven to 375°F/190°C.
Arrange the pecans on a large, rimmed baking sheet and bake until browned and fragrant, about 12 minutes.
While the nuts are still warm, return them to the bowl and add the oil, rosemary, and salt to taste, tossing to evenly coat.
Return the mixture to the baking sheet, set the sheet on a wire rack, and let cool to room temperature.
