You know the Juicy Lucy, right? It's a cheese-stuffed burger that was born in Minneapolis in the 1950s, and legend has it that it got its name when the first patron took a bite and exclaimed, "That's one juicy lucy!" Well, my friend Erin Meister, who blogs as The Nervous Cook, sent me her take on it: a marinated portobello mushroom cap stuffed with a runny-yolk egg. A total umami bomb and, like the Juicy Lucy, a mess to eat. But when you're cooking for yourself who cares if you have egg on your face? Erin marinates the mushroom in a miso-vinegar mixture, but since I usually have Sesame Miso Vinaigrette on hand, it's perfect to use here, too. If you don't have it, substitute 1 tablespoon of white miso in 3 tablespoons of rice vinegar. If you don't have a grill, don't sweat it; you won't get the smoky tinge, but this works just fine instead, using a cast-iron skillet or grill pan fitted with a lid (or aluminum foil).
