Cook rice according to packet instructions. Spoon into a large ovenproof 10-cup capacity baking dish. Top with flaked tuna. Set aside.
Boil eggs over medium heat for 6-7 minutes. Drain and cool. Peel and halve.
Meanwhile, melt butter in a saucepan over medium-high heat. Add onion and cook, stirring, for 3 minutes or until softened. Stir in flour and cook for a further minute. Pour in milk and cook until the mixture boils and thickens, about 5 minutes. Stir in Dijon, season with salt and pepper and add half the parmesan. Pour over rice and arrange broccolini across the top.
Preheat oven 180°C (fan-forced). Combine remaining parmesan, panko crumbs, oil and garlic together and scatter over the top. Bake for 20 minutes or until golden and heated through. Remove mornay from oven and nestle eggs into the top. Bake for a further 5-10 minutes or until heated through.