Preheat oven to 350 degrees. Wash them thoroughly and dry with paper towel. Cut off the very top and bottom of the beetroot and cut each beet into half.
Line baking tray with aluminum foil. Line beets on the tray with the flat side down. Brush them with olive oil. Cover the beets with another aluminum foil this time wrapping foil around each beet tightly. Roast them for 30-45 minutes. Check with a knife to make sure it goes through smoothly.
Let them cool down and then peel the skin off using a paper towel. Keep refrigerated in airtight container for up to 1 week.