Preheat oven to 180C/350F.
Cook pasta per packet directions, minus 1 minute. Drain, rinse under tap water to stop it sticking together, set aside.
Meanwhile, make the sauce. Heat an ovenproof skillet over medium high heat. Add garlic and onion, cook for 3 minutes until golden. Add tomato, water/chicken stock, herbs, salt and pepper. Stir, bring to simmer, lower heat to medium and simmer energetically for 5 minutes (stir every now and then) until it thickens.
Adjust salt to taste. Also add a touch of sugar if it tastes a bit sour (depends on quality of tomato).
Turn the stove off, add pasta, stir in.
Add tuna and GENTLY stir it in with anchovies – don’t break up the tuna so it disintegrates into mush. Leave some chunks on the surface (nice when it is golden).
Drizzle with oil, top with cheese then bake for 20 minutes until golden and you get those nice crusty bits you see in the photos.
Stand for 3 minutes then serve!