I want to make macaroons but will have up to 5 egg yolks left over. What can I do with them all, that isn't mayonaise!!
Egg yolks are ideal for thickening so a good way to use them up is by making a "real" custard (creme anglaise) to spoon over a dessert, use in a trifle or make into creme brulees, home-made ice cream, custard tart or creme caramel. Yolks also whisk up well so you could try zabligone or look for recipes which have a mousse base made with egg yolks and sugar or sugar syrup.
On the savory side you could try an egg-thickened soup such as avgolemono soup or Nigella's Lemon Risotto (see recipe below). Quiches are also very good made with just egg yolks. Egg yolks also make a very good glaze for pastry as just using the yolk gives the pastry a deep golden colour (a yolk-only egg wash is sometimes referred to as "gilding").
It is also possible to freeze egg yolks but you need to first whisk the yolks with either a pinch of sugar or a pinch of salt to stop them from coagulating. Thaw the yolks overnight in the fridge and use straightaway.The yolks should be fine to use for sauces and glazing pastry but may not whisk up as well as fresh yolks so are not suitable for zabligone and mousses.