To make this pot pie, preheat your oven to 400°F and set a large oven-safe skillet over medium heat.

Add the olive oil, then toss in the diced onion, celery, and carrots. Sauté for a few minutes until they begin to soften, stirring occasionally so they don’t brown too quickly.

Add the sliced mushrooms and garlic, cooking until the mushrooms release their moisture and start to soften.

Next, stir in the shredded rotisserie chicken and let everything warm through.

Add the butter and allow it to fully melt, then sprinkle the flour over the mixture. It will look a bit dry at first, but trust the process. Keep stirring as the flour coats the vegetables and chicken.

Then, slowly pour in the chicken broth and milk, stirring constantly to avoid lumps.

Add the bouillon (if using), Dijon mustard, thyme, and rosemary. Continue stirring until the sauce thickens into a creamy, silky consistency.

Fold in the peas and grated parmesan until fully combined. Remove the skillet from the heat.

Now, roll out your thawed puff pastry so it’s slightly thinner than it comes packaged. Cut it into squares or rectangles and arrange them in a single layer over the pot pie mixture.

Whisk your egg, brush it generously over the pastry pieces, and sprinkle with sesame seeds.

Finally, transfer the skillet to the oven and bake for 30–35 minutes, or until the puff pastry is deeply golden, crisp, and beautifully puffed.

Remove from the oven, serve immediately, and enjoy!