Preheat the oven to 375F. Grease a 11 x 2.3 inch pie dish (or something similar with 2L or 8cup capacity – a 12-inch cast iron pan could work too).

To a high sided skillet or pot melt 2 tablespoons butter with the olive oil over medium-high heat. When the butter is melted, add the spinach and stir until wilted, about 3-4 minutes. Once the spinach is wilted, add the sliced mushrooms and saute for 5-7 minutes until softened and most of the water is released from the mushrooms.

Add the diced onion and cook until softened and starting to turn golden, 3-5 minutes.

Add the minced garlic, fresh thyme leaves, minced rosemary, salt and ground pepper. Stir and cook for 1 minute, until fragrant.

Add 2 tablespoons of butter and stir until melted. Once melted, add the flour and stir to coat everything in the pan - about 1 minute. Then, slowly pour in the milk, whisking until fully combined. Add the chicken stock paste and whisk to combine.

Increase the heat to high and bring to a boil, once boiling, turn to medium-low heat and keep at a simmer, stirring often, until thickened, about 6-8 minutes.

Once the sauce has thickened, turn the heat off and stir in the shredded cooked chicken and freshly grated gruyere cheese until fully combined.

Transfer the pot pie filling to the greased pie dish.

Melt 6 tablespoons of butter. Divide the butter between the sheets of phyllo dough, lightly brushing a bit of butter onto one side of each sheet of phyllo. Then, use your hands to gather the edges of each phyllo sheet individually and gently scrunch each piece of buttered phyllo into the centre, to sort of look like a flower. Place each phyllo flower on the top of the pot pie filling and repeat until you’ve used 7 sheets of phyllo dough to cover the pot pie.