This is the easiest, most fool proof way to dice an onion. Guaranteed. I'm constantly using diced onion in many of my recipes and I try and keep already diced onion in a tupperware container to save time when I'm throwing dinner together. It's such a quick and easy ingredient to have on hand prepped and ready to go when you need it. So, here we go, 5 easy steps to dice an onion. 1. Cut the ends of your onion off. The parts that grow the root and the top. 2. With one of the flat sides down so it doesn't roll, dice in half. Peel of the outer skin. 3. Cut slits into the onion all the way down to the cutting board and as close to the back of the onion as you can without making a full slice to the back. The closer together the slices the smaller the diced onion. 4. Make cuts into the onion parallel to the cutting board in the same manner as above cutting almost all the way through the onion but not all the way to the back. 5. Finally, cut the onion from right to left until you're left with a small area with no cuts. You can rough dice that separately as there wont be much left. Cut the second onion following the same steps. And that it! Super easy and quick. You really can't mess this one up!