Drizzle oil in a large frying pan and gently cook onion and garlic until soft. Add the pesto and fry 30 seconds. Add the passata, salt and pepper and stir through. Simmer 2 minutes, stirring occasionally.
Meanwhile, cook the pasta until al dente in boiling salted water.
Add the frozen peas and cream cheese to the passata mixture and stir though. Stir in the basil. Taste for seasoning.
Drain the pasta and mix with the passata. Transfer to a baking dish and sprinkle the cheese over the top. Bake 10 minutes. Serve with crusty garlic bread.