1 1/2 pounds portobello mushrooms
1 teaspoon smoked paprika
3/4 teaspoon salt
1/2 teaspoon pepper
1. Heat the oven to 400°F and evenly space the two oven racks. Line 2 rimmed baking sheets with foil and grease each with 1 tablespoon oil. Remove the stems from the mushrooms and save for another use. Slice the caps crosswise as thin as you can manage; transfer them to the prepared sheets.
2. Arrange the mushroom slices into a single layer and sprinkle with the paprika, salt, and pepper. Transfer the pans to the oven and roast, undisturbed, until the mushrooms release their water and the pan is almost dry again, 20 to 30 minutes.
3. Lower the heat to 325°F and continue to roast the slices undisturbed until they dry and shrivel a bit and release evenly from the pan, another 5 to 10 minutes. Enjoy hot or at room temperature, or cool completely and store in an airtight container in the refrigerator for up to a week.