Start by taking half of a peeled onion
When slicing, try to not let your fingers stick out and instead use your knuckles to rest the knife against.
Use the knife to slice vertically down the onion, as you cut the onion the weight of the knife should push through it. Try to not cut too aggressively or fast until you’ve got the hang of it. As you slice the tip of the blade should stay in contact with the chopping board. Notice how the knife rests on my knuckle while slicing, keeping the fingertips safe.
This will result in semi-circle strands of onion and is probably the most commonly used method of slicing an onion. For smaller, quarter circle strands just cut the onion on half through the root again.
Try to keep the spacing between slices the same so the onion is all roughly the same size (unless cutting for something that will get blitzed i.e soup, curry etc). This is so it all cooks at a similar rate and you don’t end up with raw bits of onion and overcooked bits of onion in the same dish.
Recipes and Stuff 