You can’t have your cake and eat it.
A proverb about choices.  Where resources are limited you have to choose whether to save or to use something.

Either a feast or a famine.
A feast is plenty of food and a famine is a shortage.  This idiom is used to describe a situation where the availability of resources or helpers is unpredictable.

Starving in the midst of plenty is an idiom.  If someone is too lazy to prepare food or shop or hunt…

As many times as you’ve had hot dinners is often said to children in an attempt to convey how experienced an older person is.

You’ve cooked your goose.  Cooking is an irreversible process.  This metaphor is about not being able to reverse the effect of one’s actions.

As flat as a pancake is a simile.

Drop a clanger means to make a mistake.  A clanger is a pasty with a savoury filling at one end and a sweet filling at the other, traditionally taken to work by Cornish tin-miners.  Dropping one might mix the two sorts.  http://en.wikipedia.org/wiki/Bedfordshire_clanger

A raspberry is a noise made by blowing through pursed lips.

The cream always rises to the top – describes milk and society.

Crème de la crème is a similar idea adopted from French – the cream of the cream or the very best.

A la carte is individual items from a menu.

Cheese-paring is a form of economy including scraping the mould off cheese, so that little is wasted.

A square meal is usually served on a round plate.

A half-baked idea has not been thought through.

Piping hot is so hot that it makes a noise.

Toad-in-the-hole is Yorkshire pudding with sausages baked in it.

Cook’s mistake is a culinary attempt, which has not turned out quite as planned.

A burnt offering is sometimes a cake which has been forgotten in the oven.

Originally it was an offering made to God to atone for sins.  Leviticus 1:4