What you need: A baking sheet, tinfoil and that hard-as-a-rock avocado What you do: Wrap the whole fruit in tinfoil and set it on the baking sheet. Pop it in the oven at 200°F for ten minutes, or until the avocado is soft (depending on how hard it is, it could take up to an hour to soften). Remove it from the oven, then put your soft, ripe avocado into the fridge until it cools. Why this works: Avocados produce ethylene gas, which is typically released slowly, causing the fruit to ripen. But as the avocado bakes in tinfoil, the gas surrounds it, putting the ripening process into hyperdrive. Guac and avocado toast for all!