1: Bring a large pan of water to the boil. Add the pasta shells and cook for 10-12 minutes, or according to the packet instructions. When it’s nearly done, add the frozen peas to the pan for the last 1-2 minutes of cooking. Keep back ½ a mug of pasta water (to use later), then drain the pasta and set aside. 

2: In the same pan, heat the vegetable oil over a medium heat. Slice up the sausages and add them to the pan, cooking for 1-2 minutes to heat through. 

3: Crumble in the stock cube and add the ½ mug of pasta water, then add the mustard and cream cheese. Stir it all together to get a light, loosened sauce, then season with pepper. Finally, add the cooked pasta and peas to the pan and give it a stir to coat everything in the sauce. 

4: Spoon it onto plates and sprinkle over the parmesan, if using. Now tuck in.