Step 1

Bring 1 1/2 cups water to a simmer in a saucepan. Whisk in miso until it dissolves completely (do not let it boil). Gently crack egg into a small bowl, then gently slide it into the simmering broth. Cook until the white is just set and the yolk is still runny, about 2 minutes.

Step 2

Add spinach and cook just until wilted, about 1 minute. Sprinkle with scallions and season with salt and pepper.