Bring a large pot of salted water to the boil. Tip in the pasta. Cook until al dente, drain reserving a cupful of pasta water.
Heat the oil in a large frying pan over a medium heat. Fry the onions until starting to brown. Tip in the sun-dried tomatoes and fry for a further minute.
Tip in the hummus, spinach, and a splash of pasta water. Mix well until the spinach has wilted. Stir through the pasta, basil and half of the lemon juice. Add an extra splash of pasta water if needed. Season to taste with salt, pepper, and chilli flakes.
Serve with the remaining lemon juice.
