First,whisk milk, eggs and vanilla together in a jug. Sift flour into a large bowl. Stir in sugar. Make a well in the centre. Add milk mixture. Whisk until just combined. Finally Heat a large non-stick frying pan over medium heat. Spray with cooking oil. Using 1/4 cup mixture per pancake, cook 2 pancakes for 2 minutes or until bubbles appear on surface. Turn and cook for a further 1-2 minutes or until cooked through. Transfer to a plate. Cover loosely with foil to keep warm. Repeat with remaining mixture, spraying pan with cooking oil between batches.