Preheat your oven to 200°C. Chop the potato and sweet potato into 2cm 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 until golden, 25-30 mins. Turn halfway through.

Peel and grate the garlic (or use a garlic press). Zest the lemon and finely chop the chives (use scissors if easier). TIP: Discard any tough stalks from the cavolo nero.

Drizzle the sea bass with the olive oil for the marinade (see ingredients for amount). Season with salt and half the Cajun spice mix. Rub this onto both sides of the fish. In a small bowl, mix the remaining Cajun spice mix with half the chives, a pinch of lemon zest, a squeeze of lemon juice and the olive oil for the dressing (see ingredients for amount). Season with salt and keep to one side. IMPORTANT: Wash your hands after handling raw fish.

Heat a drizzle of oil in a large frying pan on high heat. Add the cavolo nero and a splash of water and cover until wilted, 3-4 mins. Remove the lid, add the garlic and stir-fry for 1 min more. Season to taste with salt and pepper. Transfer to a large bowl and cover to keep warm. Wipe the frying pan clean with some kitchen paper - we'll use it to fry the fish.

Put your (now empty) frying pan on medium-high heat (no oil). Add the sea bass to the pan, skin-side down, and cook until the skin is golden brown, 2-3 mins, then turn over and cook for a further 2 mins. TIP: Don't move the fish while it's cooking skin-side down or you won't get a crispy skin. IMPORTANT: The fish is cooked when opaque in the middle.

When the potatoes are cooked, add them to your bowl of cavolo nero and roughly mash. Mix in a knob of butter (if you have any) and the remaining chives. Season to taste with salt and pepper. Serve your mash on your plates topped with the fish and a drizzle of chive dressing. Enjoy!