Cut the beets in half and trim the roots off. Place the beets and sweet potato in a steamer basket or on the trivet. Add 1 cup of water to the inner pot and place the steamer basket inside. Lock the lid into place. Select Pressure Cook or Manual, and adjust pressure to High and the time to 6 minutes. After cooking, quick release the pressure.
Unlock the lid. Remove the vegetables and let them cool slightly, then peel and cut into 1 inch chunks. They should be softened, but not completely cooked through. Place them on a baking sheet. Drizzle with the olive oil and sprinkle with the salt. Gently toss to coat.
Roast the vegetables for 8 to 10 minutes, or until cooked through and browned in spots on the outside. Remove from the oven and sprinkle with the rosemary. Return to the oven for just a minute to bloom the aroma and flavor of the rosemary, then serve.