Wash 2 untreated oranges in hot water, grate them dry and tear off the zest. Peel all oranges so that the white skin is completely removed. Cut oranges into slices. Steam orange zests in a small pot covered with a little water for 3-4 minutes, remove and drain.
Caramelise the sugar and 100 ml water in a small pot until golden brown. Arrange orange slices and zests on a plate or shelf. Pour over the still simmering caramel and serve immediately with the ice cream.