Pestle and mortar

The best investment you can make for grinding and crushingn is a heavy, unglazed porcelain bowl (the mortar) with a rounded tool (the pestle) that pounds anything and everything.

It will last a lifetime (Delia uses Milton Brook), and serve you in countless ways: with it you can bruise rosemary leaves to release their fragrant oils, crush whole roasted spices, pound the leaves of basil and other herbs, and reduce a clove of garlic and some flakes of salt into a creamy mass in seconds - and there is absolutely no better way to combine ingredients for a salad dressing.