Step 1 Heat oil in a large saucepan over medium heat. Add onion and garlic. Cook, stirring occasionally, for 5 minutes or until onion is soft. Add mince. Cook, stirring with a wooden spoon to break up mince, for 15 minutes or until browned.
Step 2 Add carrot. Cook, stirring, for 5 minutes. Add tomato paste. Cook, stirring, for 2 to 4 minutes. Add crushed tomatoes. Increase heat to high. Bring to the boil.
Step 3 Reduce heat to medium-low. Simmer, uncovered, for 20 to 30 minutes or until sauce thickens. Season with salt and pepper.
Step 4 Meanwhile, place potatoes in a saucepan. Cover with cold water. Bring to the boil over high heat. Reduce heat to medium. Cook, uncovered, for 6 to 8 minutes or until just tender. Drain. Add potatoes and tomatoes to mince mixture.
Step 5 Preheat oven to 180°C. Spoon mixture into a 8-cup capacity ovenproof dish. Sprinkle with bread and cheese. Bake for 40 to 50 minutes or until golden and heated through (cover during cooking if top is browning too quickly). Serve.