Step 1: In a large, oven-safe skillet or Dutch oven, melt 2 tablespoons of butter over medium heat. Add the diced onion and cook until softened, about 5-7 minutes.
Step 2: Stir in the minced garlic and cook for another minute until fragrant.
Step 3: Sprinkle in the flour, stirring constantly for 1-2 minutes to create a roux, which will thicken your potpie filling.
Step 4: Gradually whisk in the chicken broth, making sure to scrape up any bits from the bottom of the pan. Continue whisking until the mixture thickens, about 3-5 minutes.
Step 5: Pour in the heavy cream and bring the mixture to a gentle simmer. Season with dried thyme, salt, and black pepper. Taste and adjust seasonings as needed.
Step 6: Stir in the shredded cooked chicken and frozen mixed vegetables. Cook for 5 minutes, or until the vegetables are tender-crisp and the filling is heated through.
Step 7: Remove the skillet from the heat.
Step 8: Preheat your oven to 400°F (200°C).
Step 9: In a medium bowl, combine the Cheddar Bay Biscuit mix with 1/2 cup of cold milk and 1/2 cup of shredded cheddar cheese. Mix until just combined – do not overmix, as this can make the biscuits tough.
Step 10: Drop spoonfuls of the biscuit dough evenly over the hot chicken potpie filling in the skillet. You want enough to cover the top but leave small gaps for steam to escape.
Step 11: Bake for 18-22 minutes, or until the biscuits are golden brown and cooked through.
Step 12: While the potpie bakes, prepare the garlic herb butter. Melt the remaining 1/4 cup of butter and stir in the contents of the seasoning packet from the biscuit mix.
Step 13: Once the potpie is out of the oven, immediately brush the tops of the hot biscuits with the garlic herb butter.
Step 14: Let the Cheddar Bay Biscuit Chicken Potpie rest for 5-10 minutes before serving. This allows the filling to set slightly.