In a medium saucepan, combine the broth and tomato sauce and heat over low heat until just
warmed, 4 to 5 minutes.
In a large saucepan, heat the olive oil over medium-high heat. Add the onion and cook, stirring, until softened, 3 to 4 minutes. Add the zucchini and garlic and continue to cook, stirring, until those are softened too, 3 to 4 minutes. Stir in the rice and cook, stirring occasionally, until it is glossy in appearance, 2 to 3 minutes.
Add the wine, stir and let the liquid evaporate.
Stir in the salt. Add the warmed tomato broth ½ cup at a time, stirring occasionally. When the broth has just about been completely absorbed by the rice, add another ½ cup. Continue to cook and stir and add broth in ½ cup increments until all of the broth has been absorbed and the risotto is tender, but still firm to the bite, 20 to 25 minutes.
Remove the pan from heat and stir in the cheese, basil and pepper to taste. Serve immediately.