Shortcrust pastry: Start by adding the shortcrust pastry to a casserole dish. Make sure to cut a large amount of pastry to fit the base surface of the casserole dish and the sides. Add parchment paper on top of the shortcrust pastry and beans. Place in the oven and bake for ten to fifteen minutes. Afterward, remove the casserole, beans, and parchment paper from the oven. At this time, the shortcrust pastry will have formed into a steady shape. Place the casserole into the oven again and bake for another ten minutes. Remove from oven and set aside.
Cook the filling: Add finely minced garlic to a pot on medium-high heat. Add olive oil and cook for two to four minutes. When the garlic has browned, add the chopped chicken breasts. Add the chopped spring onions, fresh cream, Dijon mustard, and spices into the pot. Stir well and mix. Add the chopped parsley. Add the flour and mix well. Let it simmer on medium-low heat. The sauce should take about fifteen to twenty minutes to thicken up. Keep stirring the pot every few minutes.
Assemble the pie: Add the filling to the shortcrust pastry and cover with puff pastry. Coat the puff pastry with a whisked egg. Bake for thirty minutes until the puff pastry has a golden brown colour. Remove from the oven. Let it rest for ten minutes and serve