If using fresh oranges, remove the peel and pith. Suprême the oranges (see page 95) into a small bowl and squeeze the juice from the membranes over them. Or pour the canned oranges and juice into a bowl. Stir in the vanilla.Transfer the oranges and juice to a tall glass. Add the ice cream and top off with club soda. Stir once and serve immediately, with a long spoon. Note: To suprême citrus, cut off the very top and bottom of the fruit. Working over a bowl to catch the juice, peel off the skin and pith. Using a sharp knife, carefully cut between the flesh and membrane of each section on both sides to remove clean, naked pieces of citrus. When complete, squeeze the membranes to release any remaining juice.