You'll have this dish on the table in under 15 minutes. (No, we're not kidding.) Serving it with lots of crusty bread is a must: You'll want to sop up every last drop of broth. We love the hint of anise from the tarragon.
Heat oil in a large pot over medium heat and cook shallot, stirring, until tender, about 5 minutes. Add wine and reduce mixture by half. Add tomatoes and corn and cook, stirring, about 1 minute. Season with salt and pepper.
Add mussels to pot and cook, covered, until shells have opened, 4 to 5 minutes. (Discard any unopened shells.)
Stir in tarragon. Drizzle toast with oil and serve with mussels. Garnish with tarragon leaves.
Tomato Talk You don't need cherry tomatoes for this broth -- any type will do. (Cut bigger varieties into 1-inch chunks.)