Avocados spoil quickly after ripening, often making it necessary to purchase them a day or two before you plan to use them. Sometimes there are no ripe avocados available in the grocery store or the unripe ones purchased a few days before have not finished ripening. Instead of skipping the avocado in your recipe, you can ripen avocados in the oven with little effort in less than a day. They will be ready when you need them for your favorite dip, sandwich or other dish.
Place the avocado in a brown paper bag. Fold the top of the bag down to seal.
Place the bagged avocado into a cold oven with only the oven light turned on. Leave overnight.
Check the avocado first thing in the morning. If the avocado is still hard to the touch, place a ripe piece of fruit such as an apple or banana into the bag and reseal it. Allow it to sit in the oven for an additional 3 to 5 hours.