Use 5 cups of our Boursin cheese mashed potato recipe for this dish. As the potatoes are boiling, start preparing the filling.

Melt the BUTTER in a large pan over medium-high heat. Add the diced ONIONS and CELERY, and sauté them for 3 minutes. Then, add the GARLIC and cook for an additional minute.

Increase the heat to high and add the GROUND TURKEY together with the SEASONINGS ( onion powder, dried thyme, rosemary, sage, black pepper and salt) to the pan. Cook and crumble it until it's fully cooked. Then, drain off any excess grease.

Reduce the heat to medium-high. Sprinkle FLOUR over the mixture and stir to coat.

Gradually add the CHICKEN BROTH and HALF and HALF, whisking continuously.

Add chicken BOUILLON CUBE and WORCESTERSHIRE  SAUCE, and stir to combine. Allow to simmer until the mixture gets thicker.

Mix in the FROZEN VEGETABLES, stirring to combine and heat them through. Then, take the pan off the heat.

If your skillet isn't safe for the oven or broiler, transfer the filling to a lightly greased 9 x 13-inch baking dish.

Allow the filling to cool a bit, then gently scoop warm potatoes on top. Use a silicone spatula to spread the warm potatoes into an even, smooth layer over the filling. Be gentle and avoid pressing down too hard to keep the potatoes on top.

If you like, you can use a fork to make a 'raked' design on top of the potatoes. Then, put the dish in the preheated oven and bake it uncovered for 10 minutes.

Turn the broiler to high (550 degrees) and let the top of the dish brown for about 4 minutes. Keep a close eye on it to make sure it doesn't burn. Avoid using glass or Pyrex baking dishes for this step.

Take it out of the oven and garnish with fresh thyme or parsley. Let the dish sit for 5 minutes before serving.