First the pasta. Why seashells? because they pickup the sauce better than anything.
Pasta to hot boiling water, add salt stir, bring to boil, stir again, cool the heat to a small bubbling, 15-20 mins to al dente.
Ok sauce -
quarter an onion, peel finely chop. high heat a small pan, drizzle 20c piece rice bran oil (it can take the heat), add the onion, stir finely chop a clove garlic and add.
Grab some passata pour in what makes sense for the amount of pasta you have cooked. The general rule is Less is more. bring the heat down to a simmer, add a generous salt and pepper. Mix the ionion and sauce together as the flavours of the garlic start to eminate add the fresh basil and soem english garden spinach.
leave on low simmer heat until the pasta is ready, drain th pasta and add the pasta to the sauce - fold and mix it in and then plate up. Enjoy this simple but divine dish.
If you want more complexity on th flavours try adding aregano and or thyme (fresh only of course)