1 tablespoon vegetable oil
1 medium yellow onion, sliced
1 medium carrot, chopped
4 medium plum tomatoes, diced
1 stick celery, sliced
500g ground beef
500g button mushrooms
2 tablespoons all-purpose flour, plus more for rolling
1 cup ale beer (or you can use beef or vegetable stock instead)
1 teaspoon dried thyme
Salt & pepper, to taste
250g puff-pastry, enough to cover pan
In a large, deep, ovenproof skillet (like a 10-inch cast iron skillet), heat the vegetable oil over a medium heat. Add in the sliced onion and cook while stirring until the onion is translucent. Add the carrot, tomatoes, mushrooms and celery, and continue to cook for 5 minutes, stirring occasionally with a wooden spoon. Add the ground beef and use your spoon to break it up into small pieces.
Keep stirring the mixture until all the beef is opaque and no longer pink. Sprinkle the flour over the contents of the skillet, then stir it in. Lastly stir in the ale, thyme, and a good grind of black pepper. Season with salt, to taste, then take it off the heat and set aside to cool for 10 minutes while you preheat the oven to 400F/200C. (This is a good time to clean up the kitchen!)
Dust the puff pastry with some flour and roll out into a square large enough to cover your skillet. Roll the pastry up onto your rolling pin and unroll over the skillet. Trim off any overhanging edges of the pastry. Place the skillet into the oven and bake for 25 to 30 minutes until golden and bubbling. Leave to cool for 10 minutes before serving.