Make Beef mixture. Heat oil in a large frying pan over medium-high heat. Add onion and garlic. Cook, stirring, for 3 minutes or until softened. Increase heat to high. Add mince. Cook, stirring with a wooden spoon to break up any lumps, for 5 minutes or until browned. Season with salt and pepper. Add passata, paste and oregano. Stir to combine. Bring to the boil. Set aside.

Make Bechamel. Melt butter in a medium saucepan over medium-high heat. Add flour. Stir until smooth. Cook, stirring, for 1 to 2 minutes or until mixture bubbles and turns golden. Whisk in milk. Cook, whisking, for 1 to 2 minutes or until mixture boils and thickens. Remove from heat. Season with salt and pepper.

Preheat oven to 200C/180C fan-forced.

Combine cheeses in a bowl. Add 3/4 cup of cheese to bechamel. Whisk until smooth. Spread 1/2 cup of beef mixture over the base of a 24cm x 36cm baking dish. Cover with 4 1/2 sheets of pasta. Spoon half of the remaining beef mixture over pasta. Spoon over 1/3 of the bechamel. Repeat layering with half the remaining pasta, remaining beef mixture and half of the remaining bechamel. Cover with remaining pasta and bechamel. Sprinkle over remaining cheese. Top with pepperoni, capsicum and olives. Cover with lightly greased foil.