Start your slow cooker in the morning and by dinnertime, you’ll have deeply spiced black beans that just need a quick blend to become a velvety and vegan black bean soup. While not essential, a smidgen of baking soda helps the beans soften so they end up almost fudgy. Blending some of the beans with their liquid gives the soup body; for a very smooth soup, purée the whole mixture. A little vinegar and a flourish of toppings keep it from being one-note. Leftovers will thicken overnight, so thin as needed with water or turn them into refried beans.