This has us crying tears of happiness... And that's not just from chopping onions, although we will be doing just that if this food hack is to be believed. Avocado roulette is a concept we are very familiar with - not ripe enough, RIPE! EAT IT QUICK, brown, it's over. However, according to the folk at The Kitchn, you can preserve your perfectly ripe avocado for days in the fridge without it browning, just by popping an onion in with it. First of all, preserve the half with the pip still in, as less surface area is exposed to be oxygenated, less will go brown - that's common sense. However, by placing a cut up onion into a small airtight container with your avocado, you can keep it green for days. This is because of the "sulfur compounds that the onion releases. This is the same sulfur that makes you cry when you chop onions, but it is also used as a preservative", according to the cookery site. Now, our biggest concern here is the smell of onion transferring, but apparently the avocado keeps its characteristic taste and is not affected by its pungent neighbour. We will do some investigative journalism and get back to you, but meanwhile, this is definitely a go-er for guacamole!