03Add grated tomato and stir gently until the mixture is dense. Add remaining broth, 1 cup at a time, stirring until each addition is absorbed, until the rice is creamy but al dente, 25 to 30 minutes.04Add feta and stir until melted and risotto is creamy and thick. Stir in oregano and lemon zest, and season to taste with salt and pepper. Remove from heat and serve immediately.05Note: To grate a tomato, halve crosswise and grate the cut side with a coarse grater over a strainer set over a bowl. Grate as close to the skin as possible, but discard the skin.