Step 1

Cook pasta in a large saucepan of boiling, salted water, following packet directions until tender. Drain. Transfer to a large heatproof bowl.

Step 2

Preheat oven to 180C/160C fan-forced.

Step 3

Cook bacon in a large non-stick saucepan over medium heat for 5 minutes or until golden. Add garlic and onion. Cook, stirring for 2 minutes or until onion is soft. Add to pasta.

Step 4

Melt butter in same pan over medium heat. Add flour. Cook, stirring for 1 minute or until mixture is bubbling. Gradually stir in milk until smooth. Cook, stirring constantly for 8 to 10 minutes or until mixture boils and thickens. Stir in 1/2 cup cheese and parsley. Add to pasta and bacon mixture. Toss to combine. Season with salt and pepper.

Step 5

Spoon mixture into a 12 cup-capacity ovenproof dish. Top with tomato. Sprinkle with breadcrumbs and remaining cup of cheese. Drizzle with oil. Bake for 30 to 35 minutes or until top is golden. Stand 2 minutes. Serve.