Chop up the bacon, remove the fat and heat a non stick pan. Then cook the bacon for a few minutes.
Add the rosemary and garlic, stir round to release the the flavours.
Next add the chopped tomatoes and allow to come to a simmer.
Cook the pasta.
Wash the chard, chop any huge leaves. Place into the pan and allow it to wilt down.
Chop the mushrooms and add these to the pan, allow the sauce to simmer for 5 minutes then turn off the heat and put the lid on.
When the pasta is ready mix the sauce in and serve.