Remove sausage meat from casings, pinching into rough bite sized chunks as you go
Slice tomatoes in half lengthways, and remove the seeds with either a melon baller, teaspoon or sharp knife & discard, then dice tomatoes
Meanwhile, cook pasta according to packet directions
In a large non stick fry pan, melt butter over medium heat, adding breadcrumbs & rosemary and fry until crisp then remove crumbs to small bowl and set aside
Add chorizo to the same pan, frying over medium high heat until chorizo is lightly browned & just cooked through (carefully absorb any excess oil from pan with kitchen towel/paper - see my notes)
Add ¾ of chopped tomatoes to pan and fry for 2 mins or until tomatoes start to break down
Add garlic to tomatoes in pan & fry for 30 seconds, then add wine and simmer on medium low heat for 5 mins to thicken
Add pasta & remaining chopped tomatoes to chorizo & tomato mixture & turn to coat. Turn off the heat then add basil and bocconcini giving one final quick mix to coat
Divide pasta among bowls, top with rosemary crumbs & extra basil to serve if you wish