Macaroni cheese with olives

Cook pasta in large saucepan of boiling water until just tender; drain.

Meanwhile, melt butter in large saucepan. Stir onion, garlic, capsicum and mushrooms over heat until vegetables soften. Add flour; continue stirring until mixture bubbles and thickens. Gradually stir in milk. Add paste and stir until sauce boils and thickens.

Preheat grill.

Stir pasta, olives, basil and half the cheese into sauce. Place mixture in deep 2-litre (8-cup) ovenproof dish; sprinkle with remaining cheese. Grill until cheese melts and is browned lightly.