Use a sharp knife to slit the filmy skin of the chorizo - it should then easily peel off. You don't NEED to do this, but when cooking I always prefer to. Slice the chorizo in half and then cut in to bite-sized chunks.
Heat your pan over a medium-high heat and add a drizzle of olive oil. Add the chorizo and onions and cook till the onion begins to soften and the chorizo releases its red oil. About 4 minutes, stirring regularly.
Add the chopped rosemary to the pan and cook, stirring, for about a minute.
Add the diced garlic, pepper and tomato and stir. Let it cook for 2-3 minutes until the pepper begins to soften.
Stir in the pasta, making sure to coat it in the juices from the pan.
Meanwhile, dissolve a chicken stock cube in 600ml of boiling water. You could also use ready made chicken broth.
Pour the stock into the pan and stir well.
Bring to the boil and place the lid on the pan. Allow to simmer for 10-14 minutes, until the pasta is cooked to your preference (check the packet instructions - some shapes take longer than others to cook). Give it a good stir about halfway through cooking.
If you prefer, you can cook for the final 2-3 minutes without the lid on to allow the sauce to reduce to your liking.
Sprinkle with chopped fresh parsley and some grated cheese to serve.