We’ve all been in this situation. You want avocado toast or guacamole , but can’t find a ripe avocado. Your local Whole Foods has nothing but green dinosaur eggs days that are at least a week away from usability. So what to do?There are two chief methods for ripening an avocado on short notice. The first is a weird trick involving a paper bag and an apple or banana. You take the avocado, put it and the banana or apple in the bag, and store it for a day. Bananas are best, but apples keep longer and can be reused. The other fruit, and the avocado itself, give off ethylene gas, which causes the ripening process. Trapping the gas means that the fruit ripens faster. After a day, check for ripeness. If the avocado is super unripe, give it another day.A much faster trick involves a baking sheet, tinfoil, and an oven. You wrap your rock-hard avocado in the tinfoil, place on the baking sheet, and put it in the oven at 200°F for 10 minutes. If the avocado is very unripe, this process can take up to an hour, but it’s usually much shorter than that. Then, place the avocado in the fridge and wait for it to cool. This method ramps up the ethylene gas reaction described above, speeding up the ripening process.So there you have it. Perfectly ripe avocados in a third of an episode of Girls.