Avocados are best used raw, not cooked. Although it's technically a fruit, the mild-flavoured avocado is used as a vegetable. They're creamy texture is a great heallthy alternative to mayo on sandwiches.
How to Select
Go for an unblemished skin, and flesh that gives slightly if squeezed gently (though it shouldn't actually be soft). If you buy hard ones you can ripen them quickly by putting them in a brown paper bag with a banana (keep out of the fridge).
How to Store
Once ripe, keep them in the fridge.
How to Prepare
Using a small, sharp knife, run a blade all the way around the avocado, from top to bottom. Make sure you cut in till the blade meets the stone. Twist the two halves in opposite directions to separate them. To remove the stone, ease it out with a spoon or, using a firm, swift action, stick the length of a sharp knife into it and lever out. Avocado flesh discolours rapidly on exposure to the air: to prevent this, brush with lemon juice.