Pre-heat the oven to 375 degrees. Line a muffin tin with paper liners. Combine the softened dates, almond butter, coconut milk, avocado, egg, vanilla extract, vinegar, cocoa powder, salt and baking soda in the bowl of a food processor or a blender. Mix the ingredients well until the batter is smooth. Use an ice cream scoop or spoon to place batter into the muffin tray.