Chicken Caramelised Onion And Tarragon Pie | Donna Hay

Ingredients

• 1 tablespoon extra virgin olive oil
• 1kg chicken thigh fillets, trimmed and chopped
• 3 cloves garlic, sliced
• 20g unsalted butter, chopped
• 2 tablespoons Dijon mustard
• ¼ cup (35g) plain (all-purpose) flour
• 1 cup (280g) store-bought caramelised onion
• ¼ cup tarragon leaves
• 1 x 375g sheet frozen puff pastry, thawed+