Place the almond meal and icing sugar in a food processor and whizz for 30 seconds to a fine powder. Sift into a bowl.
In a saucepan, combine the white sugar and water and cook over medium heat, stirring until sugar dissolves. Using a thermometer to check, heat to 118 degrees C.
Meanwhile, pour half the egg whites into an electric mixing bowl and beat to soft peak stage. When the syrup is hot enough carefully pour it down the side of the mixing bowl into the egg whites. Beat until the meringue cools and is shiny and thick.
Add the remaining egg whites to the almond mixture and stir to a thick paste. Beat one third of the meringue into the almond paste to lighten it, then gently fold in the rest of the meringue until the batter is smooth.
Line a baking tray with baking paper. Spoon the batter into a pastry bag and pipe flat 4cm mounds on the baking paper. Lightly tap the bottom of the baking tray to smooth the surface of the macarons.
Bake 10-12 minutes or until just firm but still pale. They should have a characteristic 'foot' around the edge. Let cool completely before filling.