I'm making a recipe that calls only for egg yolks (about 9 to be exact). What's the yummiest thing to make with all the leftover egg whites?

I have a recipe from Mc Calls cooking school called Tortoni. It is basically whipped egg whites with a hot sugar syrup, then added whipped cream and almond extract. Freeze. It is a yummy, light ice cream-like confection.

Try toasted nuts such as these http://food52.com/recipes/7943-spiced-pecans

This question comes up regularly on the hotline. Try searching the hotline for "egg whites"...

Slip one or two into scrambled eggs or omelettes: it does change the texture, but in a pleasant way. Also, they freeze perfectly, so store them up for an angel food cake.

Macarons!

Mousse and freeze or swiss meringue (meringue made in a bowl over simmering water) and freeze. Texture like you've never had before.

Homemade marshmallows of course! :)

Thank you so much!!!!

David Lebovitz's coconut macaroons (http://www.davidlebovitz.com/2005/06/an-american-mac-1/) are a go-to recipe when I need to use up egg whites. I also use 1-2 whites to create clusters when baking up a batch of granola (4 cups oats + 2 cups mix of sweetener, coconut oil, ground flaxseeds, and nuts). They freeze well, as other people have said; I also make macarons with leftover egg whites.

Chocolate Mousse

I concur with all HalfPint mentioned above. I also like to make these meringues in particular: http://food52.com/recipes/22681-basil-lemon-meringues.

You can freeze for later use. You can make a pavlova, meringue cookies, marshmallows, French nougat, eggwhite quiche, egg white omelet, angel food cake. My favorite is the pavlov, topped with whipped cream and fresh fruit.

I like to add a couple of whole eggs. some onion green pepper, potato and make a frittata.