First, make the praline. Put the sugar and lavender into a saucepan and melt over medium heat until brown and caramelized. Pour into a greased tray, cool and then pound to a fine powder. To make the ice cream, bring the milk and lavender just to the boil, remove from heat, cover and leave to infuse for 30 mins in a warm place. In the meantime beat together the egg yolks and sugar until creamy.