Bring a medium saucepan of salted water to the boil. Peel the potato and cut into 2cm chunks. Add the potato to the saucepan of boiling water and cook until easily pierced with a knife, 10-15 minutes. Drain and return to the saucepan. Add the butter, milk and the salt and mash with a potato masher or fork until smooth.

While the potato is cooking, finely chop the brown onion (see ingredients). Finely chop the carrot (unpeeled), or grate if you prefer. Pick and finely chop the rosemary leaves (see ingredients). Pick and chop the thyme leaves. Finely chop the garlic. Roughly chop the baby spinach leaves. TIP: If the thyme stems are very soft, you can chop them too!

In a large frying pan, heat a drizzle of olive oil over a high heat. Add the onion and carrot and cook, stirring, until softened, 6-7 minutes. Add the garlic (reserve a pinch for the beans), rosemary and thyme 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, water and crumbled beef stock (1 cube for 2 people / 2 cubes for 4 people). 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 garlicky green beans between plates.