Salt: there are lots of salty elements to the sauce already (anchovies, capers, olives) so go slowly when seasoning with salt. Taste as you go!

Adding sugar to tomato sauce: if you find the tomato sauce a little sour, add ½ teaspoon of sugar. It helps to balance it out.

Tuna/Mackerel: for extra protein, I sometimes add a jar/tin of tuna or mackerel to the sauce and stir together. It adds a layer of meatiness and works really well with the capers and olives.

Tomatoes: you want to use the best quality tinned tomatoes you can find. I really rate mutti.

Variations: You can add some chopped chilli in with the onions, or snip in some anchovies. A little handful of baby capers is also very nice. Add more garlic, or less depending on your taste. Add a squeeze of tomato puree. Add some black olives in at the end. Use a sprinkling of dried oregano when you sweat the onions. Sprinkle with dried chilli at the end.

Serving suggestions: this is a delicious, comforting meal all on its own. However, it is also lovely with garlic bread to mop up all the wonderful sauce and/or a fresh salad on the side.

What to do with leftovers: Transfer to an airtight container and place in the fridge for 3 days. To reheat, use a large saucepan or deep-sided frying pan and gently heat through over a low-medium heat until piping hot. Or place in the microwave until piping hot.