Cook spaghetti in a saucepan of boiling salted water following packet instructions until al dente.
Heat olive oil in a nonstick saucepan. Add garlic; fry until lightly golden and fragrant. Add bacon. Cook, stirring for 2-3 minutes then add mushrooms. Stir until mushrooms begin to soften. Pour in stock or water and bring to the boil.
Put in pasta and cook to a rapid boil. Add parsley and chives then season with salt, pepper and chicken stock powder. Dish out and serve immediately.