put the egg whites in a large clean ( otherwise the egg will not stiffen) bowl and whisk until it holds soft peaks ( to check if the the whites are stiff enough they should not drip of whisk or fall out of bowl when held upside down) Add the sugar a spoonful at a time whisking well until the mixture becomes glossy, fold in the vanilla extract with a rubber spatula. Preheat oven to 120 C /250F fill piping back and pipe 40 rosette about one inch apart onto baking parchment,Bake until crisp and dry, make sure they stay a whitish colour, about 1 hour. Cool completely before removing from sheet.