Preheat your oven to 375°F (190°C). Line a 12-cup muffin tin with liners or spray well with nonstick spray.

In a medium skillet, melt the butter over medium heat. Add chopped onion and cook until translucent, about 3–4 minutes. Add garlic and cook another 30 seconds until fragrant.

Sprinkle the flour over the onions and garlic, stirring constantly for about a minute.

Slowly whisk in chicken broth until smooth, then stir in the milk. Add thyme, salt, and pepper. Cook, stirring, until the mixture thickens and coats the back of a spoon — about 3–4 minutes.

Remove from heat and stir in the shredded chicken and thawed mixed vegetables. Taste and adjust seasoning if needed.

Roll out the puff pastry or pie crust on a lightly floured surface and cut into 12 circles (about 4 inches across). Gently press each circle into the muffin cups, spoon the chicken filling into each pastry cup, filling them nearly to the top.

Optionally sprinkle a little grated cheese on each cup. Bake for 18–22 minutes, or until the crust is golden brown and the filling is bubbling. Let cool for 5 minutes before serving.

Garnish with parsley if you like. These keep warm well and are easy to pack for lunches.