Preheat your oven to 200°C (400°F). Place the oil in a large, ovenproof skillet or frying pan over a medium-high heat. Once the oil shimmers and you see a faint wisp of smoke, it's ready.

Add the minced beef to the hot pan. Break it up with a wooden spoon. Cook for 5-6 minutes, stirring occasionally, until the beef is browned all over and you can hear a satisfying sizzle. The meat should look crumbly and dark brown, with no pink remaining.

Add the diced onion and minced garlic. Stir everything together. Cook for a further 3-4 minutes, until the onion turns translucent and soft, and the garlic becomes fragrant. You'll notice the onion releasing moisture and the pan becoming less dry.

Sprinkle over the salt, pepper, smoked paprika, and tomato purée. Stir well to coat the beef and onion. Cook for 1 minute, until the tomato purée darkens slightly and the spices smell deeply aromatic.

Sprinkle the flour over the mixture. Stir constantly for 1 minute. The flour will absorb the fat and juices, forming a thick paste that clings to the beef. This is your roux, and it's the secret to a luscious, thick sauce.

Slowly pour in the beef stock, stirring continuously. The mixture will thicken almost immediately. Then pour in the double cream, stirring until the sauce is smooth and velvety. Bring the sauce to a gentle simmer. You'll see small bubbles breaking on the surface. Cook for 2 minutes, until the sauce has thickened enough to coat the back of a spoon.

Remove the pan from the heat. Stir in the frozen peas and half of the grated cheddar cheese. The residual heat will warm the peas through and melt the cheese into the sauce. The sauce should look glossy and rich.

Arrange the frozen tater tots on top of the beef mixture. Place them in neat rows, slightly overlapping, covering the entire surface. Sprinkle the remaining cheddar cheese over the tater tots. Transfer the skillet to the preheated oven.

Bake for 25-30 minutes. The casserole is ready when the tater tots are deep golden brown and crispy, and the sauce is bubbling up around the edges. You'll hear a gentle bubbling sound when you pull it from the oven. Let it rest for 5 minutes before serving to allow the sauce to set slightly.