Cover the potatoes with cold water in a pot and let it come to a boil on high heat. Once it’s boiling turn the heat down to medium and let the potatoes simmer for 10 minutes

Sprinkle the fish fillets with salt and pepper and set aside.

Drain the potatoes, let them cool for a minute, then slice them into bite-size pieces, keeping any smaller pieces whole. Throw them into a bowl and toss them with 2 Tbsp of olive oil, and lots of salt and pepper. Don't wash this bowl! You'll use it once the potatoes come back out of the oven.

Turn your broiler on high.

Line a baking tray with parchment paper and arrange the fish fillets on it. Drizzle with the remaining olive oil. Now pour the potatoes onto the tray, filling in the areas around the fish. It should all be able to share a tray.

Broil the fish and potatoes on the oven shelf one down from the top for 8 to 15 minutes. The time will depend on how big your fillets are so consider it. I used tilapia that were quite thin, but I cooked them from frozen, so they were perfect after 10 minutes. So just keep an eye on them. They are done when they flake apart when you apply gentle pressure with your finger.

While the fish and potatoes bake, make the chimichurri sauce! Add the rest of the ingredients except for the water to a food processor and blitz until you have a smooth paste. Keep blitzing the sauce and drizzle the water into it until it becomes a thick, yet pourable puree. Taste and add more lime juice and salt to your taste.

Remove the fish and potatoes from the oven. Toss the potatoes back into the bowl you mixed them in before and add a few spoonfuls of chimichurri. Toss and coat!

Drizzle copious amounts of chimichurri sauce all over the fish and serve.