In the bowl of your mixer with the whisk attachment, beat the egg whites on medium speed until small bubbles start to form. Then increase the speed to high and beat until stiff peaks form. Gradually incorporate the sugar, adding about 2 tablespoons at a time. Once all of the sugar has been added, beat on high for about 5 minutes. The meringue should be stiff, glossy and able to hold it’s shape on a spoon or whisk, even when turned upside down. Scrap down the sides of the bowl. Add the vanilla extract and lemon juice and beat for 1 minute more.