Use avocados that are perfectly ripe and give slightly when pressed, since under ripe fruit tastes grassy and over ripe fruit can turn bitter. For the smoothest texture, blend a full minute and scrape the sides so no avocado streaks remain. Store leftovers in an airtight container in the fridge for up to two days, pressing a piece of plastic wrap directly onto the surface to keep the top from browning. Freezing is not recommended. Try it topped with fresh berries, a little orange zest, cocoa nibs, coconut cream, or chopped nuts.