Peel bananas from skins and slice very thinly. Place on a baking tray lined with baking paper. Brush the bananas with olive oil or splash them with lemon juice. Cook bananas in the oven at 50-70 degrees for 1 hour-3 hours with the door ajar. In the microwave on parchment for 6 minutes at 600 watts. If they are not roasted enough, add a couple more minutes.
