Boil the rice in salted water for 10 minutes, before draining, plunging in cold water, draining, and mixing in the olive oil and parmesan.
Meanwhile, cook the beef and onion in a large pan over medium-high heat, breaking the beef apart as it cooks, about 10 minutes.
Add the garlic, red pepper flakes, fennel, and tomato paste, mix and cook until fragrant, about a minute.
Add the tomatoes, Italian seasoning, and balsamic vinegar, bring to a boil, reduce the heat and simmer for 10 minutes, before turning off the heat.
Grease a large baking pan and layer half of the rice over the bottom followed by half of the sauce, and half of the cheese, the remaining rice, sauce and cheese.
Bake in a preheated 350F/180C oven until the sides are bubbling and the cheese is melted lightly golden brown, about 30 minutes.
