Combine egg whites and Cream if Tartar then beat until foamy. Gradually add sugar, beating continuously until stiff and glossy. Stir in vanilla. *Tip: It is easier to get the egg whites to stiffen up when it is at room temperature.
Put your waffle cups in your muffin pan, or just let it stand on a cookie sheet.
Put your meringue in a piping bag fitted with your preferred tip. Wilton #1M is the common choice.
Fill each waffle cup with meringue, leaving a small cavity in the middle to put the custard later.
Bake for 20 mins or until golden brown on top and it feels dry to touch. Lower temperature to 270F and continue baking for additional 10 minutes to completely cook the meringue.
Remove from oven. Set aside.
In a saucepan, combine milk sugar (if adding) and cornstarch in a saucepan over low heat until reduced to 2 cups. Add sugar, butter, and vanilla extract, stirring constantly. Remove from heat.
Beat egg yolks in a bowl. Add a little of the milk to the egg yolks, stir.
Gradually add yolk mixture by spoonfuls back into the saucepan, beating constantly. Stir well to avoid curdling.
Stir, stir and don’t let the custard stay still or the bottom will burn. Once it reaches the
consistency of a paste (not the hard one okay), turn off heat and set aside to cool.