Beef and Mushroom Pie

While the potatoes boil, heat a large frying pan on high heat (no oil).
Once the pan is hot, add the beef mince and fry until browned, 5-6 mins. Use a spoon to break it up as it cooks. IMPORTANT: Wash your hands and equipment after handling raw meat. The mince is cooked when no longer pink in the middle.
Meanwhile, halve, peel and chop the onion into small pieces. Peel and grate the garlic (or use a garlic press).
Once the mince has browned, drain and discard any excess fat. Add the flour (see ingredients for amount) and cook for 1-2 mins, then transfer to a plate and set aside.

Trim the carrots, then halve lengthways (no need to peel). Chop into roughly 1cm wide, 5cm long batons.
Pop the carrots onto a large baking tray. Drizzle with oil, season with salt and pepper, then toss to coat. Spread out in a single layer.
When the oven is hot, roast on the top shelf until tender, 20-25 mins. Turn halfway through.

While the carrots roast, pop the (now empty) frying pan on medium-high heat with a drizzle of oil.
Once hot, add the onion and mushrooms to the pan and fry until softened, 4-5 mins.
Stir in the garlic and tomato puree. Cook for 1 min more, then add the cooked mince back into the pan with the beef stock paste and water for the sauce (see ingredients for amount).
Bring to a boil, then lower the heat and simmer until thickened, 1-2 mins.

Once ready, transfer the pie filling to an appropriately sized ovenproof dish.
Cover with the puff pastry (see ingredients for amount), trimming off any excess. Press some of the pastry over the side of the dish if you can, or just sit it on top. Make a small hole in the middle - this allows the steam to escape. TIP: Brush the pastry with a little milk if you have some.
Bake the pie on the middle shelf of your oven until golden brown, 12-15 mins.