Tuna Melts with Roasted Bell Peppers

Position rack in upper third of oven; heat broiler to high. Line a baking sheet with foil; place bell pepper halves on it, skin-side up. Broil until the skin is nicely charred, about 15 minutes. Transfer to a large bowl, cover tightly with plastic wrap and let steam for 10 minutes.

Meanwhile, stir tuna, celery, mayonnaise, dill, shallot, mustard and pepper in a medium bowl. Arrange English muffins, cut-side up, on the foil-lined pan. Divide the tuna salad evenly among them.

Peel the peppers and slice into 1/4-inch-thick strips. Divide the strips among the sandwiches and top each with a slice of cheese (tear it into smaller pieces if it hangs over the edge). Broil until the cheese begins to turn golden and bubbly, 2 to 3 minutes.