Step 1

Arrange a rack in the middle of the oven and heat the oven to 400°F.

Step 2

Place 1 (6-ounce) box Stove Top stuffing in a large bowl. Drizzle with 1 cup hot tap water and stir with a fork until evenly moistened. Set aside, fluffing occasionally with the fork as the water is absorbed.

Step 3

Place 1 (16-ounce) bag frozen mixed vegetables in a colander and rinse with hot tap water until thawed slightly and the pieces don’t stick together; let sit in the colander to drain.

Step 4

Place 2 1/2 cups or 2 (10.5-ounce) cans chicken or turkey gravy and 1/2 cup sour cream in a large bowl and whisk until smooth. Add the vegetables and 4 cups cooked, shredded chicken or turkey (about 1 pound). Stir until everything is evenly coated with sauce. Taste and season with kosher salt and black pepper as needed.

Step 5

Transfer the mixture to a 9x13-inch or other 3-quart baking dish and spread into an even layer. Fluff the stuffing mixture with the fork, then transfer on top of the chicken mixture in an even layer. Cut 2 tablespoons unsalted butter into 12 pieces and scatter evenly over the stuffing.

Step 6

Bake until the stuffing is browned and the casserole is bubbling around the edges, about 30 minutes. Let cool for 10 minutes before serving.