1) In a large saucepan, heat the stock and water over medium-low heat.
2) In a risotto saucepan or large skillet with a rounded bottom, heat the olive oil over medium to medium-high heat. Add the onions and garlic to the pan and sauté to soften, about 3 to 4 minutes. Stir in the rice and add the zest of one lemon. Heat the rice for 1 to 2 minutes, then add the wine and cook until evaporated.
3) Add in the hot stock, a few ladles at a time, and stir for a minute with each addition, to develop the starch and creamy aspect of the rice. Total cooking time will be about 18 minutes or so. Keep adding the stock each time the pan starts to become dry at the edges.
4) While the rice cooks, peel a lemon, section the flesh and finely cutlet it. Sprinkle with 1/2 teaspoon of caster sugar.
5) When the rice is cooked to al dente, stir in the butter, lemon sections, juice of one lemon, cheese and herbs. Season with salt and pepper, to taste.
Transfer the risotto to a serving bowl and serve immediately.