Cook the rice according to the package directions and drain.
Preheat the oven to 390F / 200c.
Mix the cooked rice with the lemon juice, garlic powder, oregano, parmesan and black pepper.
Cut the tops off of the tomatoes and use a spoon to scoop out the seeds to hollow them out. Slice a small piece off of the bottom of each tomato so that they stand up tall.
Spoon the rice mixture into each tomato. Press it down so that it is tightly packed. Top with panko breadcrumbs and a little grated parmesan.
Place on a foil or parchment lined baking sheet and bake for 15 minutes until the tomatoes have softened.
Place under the broiler for a couple of minutes to brown the tops to serve.