Cherry tomatoes make a great base for a pasta sauce, especially in winter when larger tomatoes can lack flavour. Scorching them in the pan intensifies their sweetness, while garlicky breadcrumbs do double duty here, used to thicken the sauce and to add crunch and texutre.
Bring a large saucepan of salted water to the boil. Add pasta and cook for 10–12 minutes or until al dente. Drain, reserving 80ml (⅓ cup) pasta cooking water. While the pasta is cooking, continue with step 2.
Crush garlic, thinly slice onion and finely grate zest and juice of ½ lemon. Cut remaining lemon into wedges. Remove cavolo nero leaves from their stems, discarding stems, and thinly slice eaves.
Heat 20ml (1 tablespoon) olive oil in a large frypan over medium heat. Add breadcrumbs, lemon zest and garlic and cook, stirring, for 2–3 minutes or until breadcrumbs are golden and toasted. Transfer to a plate and carefully wipe out pan with paper towel.
Heat remaining olive oil in frypan over high heat. Add cherry tomatoes and cook, stirring occasionally, for 4–5 minutes or until tomatoes are lightly blistered and collapsed. Add onion and cook, stirring occasionally, for 3–4 minutes or until onion is tender.
Add cavolo nero to pan with reserved cooking water, season to taste and cook, stirring occasionally, for 2–3 minutes or until cavolo nero is just wilted. Stir in olives.
Add tuna with oil, lemon juice, pasta and ½ the garlic breadcrumbs and toss to combine. Toss salad leaves with your favourite dressing. Serve pasta with remaining garlic breadcrumbs and lemon wedges.