Bring a medium saucepan of salted water to the boil. Peel the potato and cut into large chunks. Cook the potato in the boiling water until easily pierced with a knife, 10-15 minutes. Drain and return to the saucepan. Add the butter, milk and the salt and mash until smooth.

While the potato is cooking, finely chop the brown onion (see ingredients). Finely chop the carrot. Pick and finely chop the rosemary leaves (see ingredients). Finely chop the garlic. Roughly chop the baby spinach leaves.

In a large frying pan, heat a drizzle of olive oil over a high heat. Cook the onion and carrot, stirring, until softened, 6-7 minutes. Add the garlic (reserve a pinch for the beans!) and rosemary and cook, stirring, until fragrant, 1 minute. Add the beef mince and cook, breaking up with a spoon, until just browned, 3-4 minutes. Reduce the heat to medium and add the tomato paste, the water and the beef stock pot. Stir to combine. Add the chopped baby spinach and stir through until just wilted, 1-2 minutes. TIP: Add a dash of water if the mixture looks dry.

Preheat the grill to medium-high. Transfer the mince mixture to a baking dish and spread the mashed potato over the top. Sprinkle with the shredded Cheddar cheese. Grill until the cheese is melted and golden, 5-10 minutes. TIP: Grills cook fast, so keep an eye on the pie!

While the pie is grilling, trim the green beans. Wash and dry the frying pan and return to a medium-high heat with a drizzle of olive oil. Cook the beans, tossing, until tender, 3-4 minutes. Add the reserved garlic and cook until fragrant, 1 minute. Season with salt and pepper.

Divide the beef and rosemary cottage pie and green beans between plates. Garnish with torn parsley leaves to serve.