Preheat your oven to 400°F (200°C). Gather all your ingredients.

In a large skillet, melt butter over medium heat. Add diced chicken and season with salt and pepper. Sauté for about 8 minutes until golden brown.

Stir in frozen mixed vegetables and cook for an additional 3-4 minutes until heated through.

Sprinkle flour over the mixture, stirring well. Gradually add chicken broth and mix continuously until thickened, about 5 minutes.

Lower heat and add heavy cream and thyme, stirring gently until smooth, about 2 minutes.

Roll out puff pastry sheets to about ¼ inch thick and cut out circles larger than muffin tin cups. Line each cup with pastry.

Spoon the filling into each pastry-lined cup. If desired, use excess pastry to cover the filling and seal the edges.

Bake for 20-25 minutes until the pastry is golden brown and puffy.

Remove from oven and let cool for about 5 minutes before serving.