Heat 1 tablespoon of olive oil in a large skillet over medium heat.

Add the rinsed mushrooms (set aside 4 or 5 whole ones for decoration later) and slice the rest. Sauté them until they’re lightly golden and have released their moisture. Remove from the pan and set aside.

In the same pan, add the chopped shallot and cook for a few minutes until soft and fragrant.

Next, stir in the diced chicken breast. Season with salt and pepper, then cook for about 10 minutes, or until the chicken is cooked through. Remove from the heat and let it cool slightly.

In a separate bowl, whisk together the eggs, heavy cream, and shredded cheese. Season with a little more salt and pepper, then add a pinch of cayenne for gentle warmth.

Finally, stir in the chopped fresh parsley.

Line a tart pan with the pie crust and gently press it into the edges. Prick the base with a fork, then brush it lightly with Dijon mustard — this adds a lovely depth of flavor and helps keep the crust from getting soggy.

Spoon in the sautéed vegetables and chicken cubes, spreading them out evenly over the base.

Next, pour the egg and cream mixture over the filling. Scatter a few diced bell peppers and a little chopped parsley on top for color and freshness.

Place the reserved whole mushrooms on the surface for a rustic, bistro-style finish.

Bake in a preheated oven at 400°F (200°C) for about 25 minutes, or until the top is beautifully golden and the filling is set.