Chicken, mushrooms and leeks pie

Ingredients

• 454 g (1 pound) of boneless chicken, half breast or thigh
• 30 ml (2 tablespoons) of vegetable oil
• 1 package of 250 g (4 cups) of Les Cultures de chez nous sliced leeks
• 454 g (1 pound) of minced mushrooms
• 15 ml (1 tablespoon) of tarragon
• 30 ml (2 tablespoons) of all-use flour
• 180 ml (3/4 cup) of chicken broth
• 2 ml (1/2 teaspoon) of salt
• Pepper
• 1 commercial shortcrust (22 cm/9 inches), thawed