First, heat the olive oil in your skillet over medium-high heat. I toss in the chopped onion and cook until it’s soft and fragrant, about 3–4 minutes. Then, I add the bite-sized chicken pieces, stirring so they brown just enough to get some color. This step builds flavor early, making the filling way more delicious than a bland one-pot dump.
After the chicken is mostly cooked through, I push everything to the side, swirl in the butter, and let it melt. Then the flour goes in—it forms a roux which transforms the filling from runny to creamy. Gradually, I whisk in the chicken broth and milk to avoid lumps. I add fresh thyme, season with salt and pepper, and let the mixture gently simmer. This thickens into that velvety sauce so comforting in every bite.
Once the sauce coats the back of the spoon, I toss in the frozen mixed vegetables. No thawing needed—they heat quickly in the hot mixture and release minimal water. Taste and tweak with additional salt or pepper as needed. This is where it really starts to look and feel like pot pie filling—creamy, chunky, colorful, and aromatic.
With the filling bubbling gently, I lay the thawed puff pastry sheet directly over the skillet. I press it down lightly around the edges to seal in the goodness. Then, I slash a couple of vents on top so steam can escape. Slide the skillet into a preheated oven (around 400°F) and bake for about 20–25 minutes, until the crust is puffed and beautifully golden.
Once the crust is crisp and flaky, I carefully bring the skillet out of the oven (use oven mitts!), and let it rest for 5 minutes. This brief rest helps the filling set just a bit so it’s easier to serve and even more comforting to eat. Scoop generous servings straight from the skillet and watch the smiles spread.