Place chicken breasts in a pot, cover with water, and simmer gently until cooked through (about 12–15 minutes). Shred or chop and set aside.

In a large pot or skillet, melt the butter over medium heat. Add the frozen mixed vegetables and sauté for a few minutes until they begin to soften.

Sprinkle the flour over the vegetables and stir until everything is coated. Cook for 1 minute to remove the raw flour taste.

Slowly pour in the broth while stirring. Let the mixture simmer and thicken — this takes just a few minutes.

Stir everything together. Season to taste with salt and pepper. Let the filling cook for about 15 minutes so it becomes thick, creamy, and well blended.

Pour the hot filling into a baking dish (around 9×13 or similar).

Mix according to package directions.

Spoon small mounds of biscuit dough over the hot pot pie mixture. Leave some space so they can puff up.

Bake according to the biscuit package instructions — usually 12–15 minutes — or until the tops are golden brown and cooked through.

Let the casserole sit for 5 minutes to thicken even more before serving.