This was my first time roasting a whole fish in the oven and it was much easier than I thought it was. Same as roasting anything, you do a bit of prep while the oven heats up, stick it in and wait! No tricks here.
Heat your oven to 225C. Coat the sweet potatoes in 1 Tbsp olive oil, season with salt and par-cook them in the microwave for about 8 minutes.
Meanwhile put the pesto, chimichurri, ¼ onion, garlic cloves, lemon zest and pepper in a small food processer/mini chopper and blitz for about 15 seconds. Add the olive oil and blitz for another 15 seconds until a slightly smooth sauce forms.
Cut 3 slits diagonally on both sides of the fish, cutting all the way to the bone on both sides. Rub the sauce all over the fish on both sides - make sure to rub it all the way into the slits as well. Make sure you retain about 2 Tbsp of the sauce.
Mix the par-cooked sweet potatoes with the onions and remainder of the sauce and spread around the fish.
Bake in the oven for 30 minutes until the fish is flaky and the veggies are tender. Serve with lemon wedges.