1. Remove puff pastry from freezer and let sit at room temperature until pliable and beginning to soften, 10 to 15 minutes.
2. Meanwhile, heat butter in a medium saucepan over medium-high until shimmering. Add onion, potato, and a pinch of salt and cook, stirring occasionally, until onion is softened and potato begins to brown, 5 to 7 minutes. Sprinkle flour over top and cook, stirring constantly, 1 minute.
3. Stir in broth and milk and bring to a boil. Continue to cook, stirring frequently, until consistency resembles heavy cream, about 5 minutes. Remove from heat and stir in frozen vegetables, thyme, 1/2 teaspoon salt, and 1/4 teaspoon pepper. Divide filling among four 8-oz. oven- and freezer-safe ramekins or disposable foil containers and let cool completely.
4. Working quickly on a lightly floured surface, roll out puff pastry until flat and seams are sealed. Using a round pastry cutter or glass, cut out four circles slightly larger in diameter than ramekins and place on each pot pie; cut a few 1" slits in top of pastry.
5. Set ramekins on a baking sheet and bake at 350 degrees until filling is hot and pastry is puffed and golden, about 40 minutes. Serve immediately.
Source: Hannaford fresh Magazine, January-February 2023