Step 1

Broil peppers 3 in. from heat until skins blister, about 5 minutes. With tongs, rotate peppers a quarter turn. Broil and rotate until all sides are blistered and blackened. Immediately place peppers in a large bowl; cover and let stand for 20 minutes.

Step 2

Meanwhile, in a small bowl, coarsely mash black beans; set aside. In a large nonstick skillet, cook and stir zucchini and onion until tender. Add garlic; cook 1 minute longer. Add corn, tomatoes, rice, seasonings and beans. Remove from heat; stir in 1/2 cup cheese. Set aside.

Step 3

Preheat oven to 375°. Peel charred skins from poblanos and discard. Cut a lengthwise slit through each pepper, leaving stem intact; discard membranes and seeds. Spoon about 2/3 cup filling into each pepper.

Step 4

Place peppers in a 13x9-in. baking dish coated with cooking spray. Bake until heated through, 18-22 minutes, sprinkling with green onions and remaining cheese during last 5 minutes of baking. Serve with sour cream.