Peel and finely chop the onion. Rinse and quarter the tomatoes, then remove the seeds and dice. Sauté the onion and the rice with 2 tablespoons of oil. Stir in the tomato paste, sauté briefly, then deglaze with the white wine. Add the tomatoes, and a little of the broth. Let the broth cook into the rice before adding more. Continue incorporating the remaining broth, like you would with risotto. Cook until the rice is al dente, but not too soft. This process should take 15-20 minutes. The amount of broth may vary.
Preheat a convection oven to 180°C (approximately 350°F).
Remove the rice from the heat, then stir in the parmesan, egg yolk, and basil. Season to taste with salt and pepper. Fill the rice into four oiled 300 ml (approximately 10 ounces) ovenproof ramekins. Press down well on the rice, and bake in the oven for 10 minutes.
Remove from the oven, rest briefly, and remove from the ramekins.
Serve garnished with the basil.