How to Make It
In a medium saucepan, heat the 2 tablespoons of olive oil. Add the onion and cook over moderately low heat until softened. Add the rice and stir over moderately high heat until it is coated with oil and sizzling, about 2 minutes. Stir in the wine and simmer until evaporated, about 3 minutes. Add the water and bring to a boil. Simmer over moderately low heat, stirring occasionally, until the water has been absorbed and the rice is tender, about 20 minutes. Transfer the rice to a bowl and let cool to room temperature.
Stir the thyme and lemon zest into the rice and season with salt and pepper. In a small bowl, blend the ricotta with the Parmigiano and season with salt and pepper. Put 2 tablespoons of the rice mixture in your moistened palm. Make an indentation in the center of the mound and fill it with about 1 teaspoon of the ricotta mixture. Fold the rice around the filling to enclose it and pat the rice into an oval. Repeat with the remaining rice and ricotta.
In a medium saucepan, heat 2 inches of olive oil to 300°. Set a rack over a large baking sheet. Put the flour, eggs and bread crumbs in 3 shallow bowls. Dredge the rice ovals in the flour, shaking off any excess. Dip the ovals in the egg, then coat with the bread crumbs. Deep-fry 5 ovals at a time until golden brown, about 2 minutes. With a slotted spoon, transfer the arancini to the rack to drain while you fry the rest. Serve the arancini hot or warm.