Persian Yogurt, Lentil, and Bulgur Soup with Browned Herb Butter

There are versions of this creamy yogurt and lentil soup all over the eastern Mediterranean. In this recipe, the onions, broth, and bulgur (dried cracked wheat kernels) simmer together and then are enriched with yogurt, egg, and a little cornstarch, to prevent the soup from curdling. A helping of the spice-simmered French green lentils (lentilles du Puy) is spooned into each bowl of soup, and it is finished with fresh mint sizzled in brown butter. It tastes like it came from a fancy