Peel and finely slice the onions. Peel and thinly slice the garlic cloves. Heat a large frying pan. When warm, drizzle in 2 tbsp olive oil. Add the onions, the cinnamon stick and bay leaf. Add a good pinch of salt and pepper. Cook for 10 mins on a gentle heat stirring now and then. The onions should not catch any colour. If they do, turn the heat down more.
After 10 mins, add the garlic cloves. Cook for a further 10 mins on the low heat, stirring now and then. The onions should be meltingly soft and translucent.
Spoon half the tub of yogurt into a bowl. Add 2tbsp cold water and whisk together. Heat a small frying pan and toast the pine nuts for 2-3 mins till golden. Tip into a small bowl.
Crumble half the pack of feta. Roughly chop the rocket. Finely chop the dill stalks, leaving the fronds whole.
Bring a pan of water to a rolling boil. Drop in the pasta with a good pinch of salt. Simmer for 8 mins till the pasta is al dente (soft with a slight bite). Drain, reserving a cupful of the cooking water.
When the pasta has 3 mins left to cook, pluck the bay leaf and cinnamon stick from the onions. Add the thinned yogurt to the pan with the onions, which should have cooked for a total of 20 mins. Stir together. Add the dill stalks, half of the crumbled feta and a good grinding of salt and pepper. Add a pinch of cayenne and stir.
Arrange the rocket in two shallow bowls. Tip the cooked and drained pasta into the pan with the yogurty, onion sauce. Stir to coat, adding a little cooking water if necessary to loosen the sauce a little. Spoon on top of the rocket. Crumble over the remaining feta. Scatter over the pinenuts and dill fronds. Dust a little cayenne pepper to taste.