Heat 1 tbsp olive oil in a pan. Brown the chicken thighs, season, and set aside.
In the same pan, cook bacon until crispy, then set aside.
Add onion and garlic, cook until soft, season, then add leeks. Cook until softened, then return bacon.
In a separate saucepan, melt butter over medium heat. Add flour, whisking continuously until a smooth roux forms. Gradually add chicken stock to the roux, whisking until thickened and smooth. Stir in the chopped chicken, parsley, tarragon, and mustard. Pour the roux into the chicken mixture, stirring until everything is well combined.
Preheat oven to 190°C. Line a pie dish with shortcrust pastry, blind bake until golden (20 mins). Fill with the chicken mixture, cover with puff pastry, and crimp edges. Brush with beaten egg yolk and bake until golden (35 mins).
For the gravy, heat olive oil and butter. Sauté shallots and garlic until soft. Add orange zest, juice, and white wine. Reduce, add stock, then thicken with cornflour slurry. Stir in Worcestershire sauce, season, and finish with butter.
For the mash, boil potatoes until tender. Drain, then mash with melted butter and milk until smooth. Season to taste.
Plate up and enjoy!
