Preheat your oven to 240°C/220°C fan/gas mark 9. Keep the butter in the fridge.
Chop the potatoes into 3cm chunks (no need to peel). Pop them onto a large baking tray. Drizzle with oil, season with salt and pepper, then toss to coat.
Spread out in a single layer. TIP: Use two baking trays if necessary.
When the oven is hot, roast on the top shelf for 20 mins - you'll roast them for longer once you've crushed them.

Meanwhile, finely chop the chives (use scissors if easier). Trim the green beans.
Peel and grate the garlic (or use a garlic press). Cut one half of the lemon into slices.
Lay the salmon fillets, skin-side down, onto a lined baking tray. Season with salt and pepper, then lay lemon slices on top. IMPORTANT: Wash your hands and equipment after handling raw fish.

When the potatoes have cooked for 20 mins, remove them from the oven.
Use the bottom of a bowl or pan to lightly crush each potato.
Drizzle the smashed potatoes with more oil, and return to the top shelf of your oven until crispy and golden, 10-15 mins.
Roast the salmon on the middle shelf until cooked through, 10-15 mins. IMPORTANT: The salmon is cooked when opaque in the middle.

Meanwhile, heat a drizzle of oil in a frying pan on medium-high heat.
Once hot, add the green beans and stir-fry until starting to char, 2-3 mins.
Stir in half the garlic, then turn the heat down to medium and cook for 1 min.
Add a splash of water and immediately cover with a lid or some foil. Cook until the beans are tender, 4-5 mins, then transfer to a bowl and cover to keep warm.

Pop the pan back on medium heat with a drizzle of oil. Add the remaining garlic and stir-fry for 30 secs.
Stir the water for the sauce (see pantry for amount) and veg stock paste. Bring to the boil and boil for 1 min.
Turn the heat down to low and whisk in the cold butter until melted and the sauce has thickened. Taste and season with salt and pepper if needed.

When everything is ready, share your ultimate roasted salmon and veg between your plates.
Stir the chives into the butter sauce, then spoon over the fish to finish.
Enjoy!