Step 1 Set a deep non-stick frying pan over medium–high heat; heat oil. Add meatballs and capsicum to pan and cook, stirring gently, for 5 minutes, or until meatballs are brown and capsicum is tender.
Step 2 Add tomatoes to frying pan with 1/3 cup water; bring to the boil. Reduce heat to low; simmer, uncovered, for 10–12 minutes, or until sauce thickens slightly.
Step 3 Meanwhile, cook fettuccine in a large saucepan according to packet instructions, adding cavolo nero (or spinach) to saucepan for last minute of pasta cooking time. Drain pasta and return to pan with meatballs and sauce; toss lightly.
Step 4 Divide pasta and meatballs among 4 bowls, scatter with basil and parmesan, and serve.