Bring a medium saucepan of salted water to the boil for the spaghetti. Pick the parsley leaves, discarding the stems. Put half the parsley, 2 tbs olive oil, ½ tsp white wine vinegar and 2 tsp water in a jug and season with salt and pepper. Blend with a stick blender until smooth (see Kitchen hack).
Step 2 — Cook spaghetti
Add three-quarters of the spaghetti* to the pan of boiling water and cook, stirring occasionally, for 12 mins or until al dente. Drain.
Step 3 — Start marinara sauce
Meanwhile, combine the tomatoes, Tuscan seasoning and a pinch of sugar in a medium deep frypan over medium-high heat. Bring to the boil, then reduce the heat to medium and cook, stirring occasionally, for 6-7 mins until slightly reduced.
Step 4 — Add seafood
Cut the fish into 2.5cm pieces. Add the fish to the sauce and stir to combine. Cover and cook for 2 mins. Stir in the prawns, cover and cook for a further 2-3 mins until the fish and prawns are cooked through. Remove the pan from the heat. Taste, then season with salt and pepper.
Step 5 — Serve up
Divide the spaghetti and marinara sauce among bowls. Drizzle with the parsley oil and scatter with the capers, chilli flakes, if desired, and remaining parsley. Enjoy!
Step 6 — Kitchen hack
If you don't have a stick blender or food processor, simply chop the parsley as finely as you can, then combine the ingredients in a bowl. It won't be as smooth and green, but it will still taste delish!