Unless you love the lingering smell of pungent, ripe onions under your fingernails hours after you peel them, blanch them to soften their odorous aroma and cut your cuticles a break. blanching onions makes them easier to peel and might even make your eyes tear up less when you slice them. Blanching softens the outermost layer of onion flesh, so unless you're using them in a soup or sauce, reserve that layer for vegetable stock.
Wash the onions and cut off the blossom and roots ends. Cut an "X" through the first layer of skin at the root end. Fill a large bowl 3/4 full of ice and top it cold water.
Bring a pot of water to boil and add the onions. Set the timer for four minutes after the water returns to a boil.
Onion rings and chopped onions need only 10 to 15 seconds of blanching.
Drain the onions in a colander when the timer sounds and tranfser them to the ice water. Chill the onions for 4 minutes.
Remove the onions from the water. Peel the onions if using immediately, or let them aire dry and store them uncovered at room temperature.