Heat the olive oil in a large saucepan over medium heat. Add the onion and cook until soft, about 4 minutes. Add the rice and cook, stirring for 1 minute. Reduce the heat then add a ladle of hot broth and cook, stirring constantly, until the liquid is absorbed. Repeat with the remaining broth, adding a ladle at a time, until the rice is tender, about 50 minutes.

Meanwhile, toss squash with 2 tablespoons of olive oil onto a baking sheet; season with salt and pepper. Roast, tossing once, until golden brown and tender, about 20–25 minutes.

After 30 minutes, add the squash to the rice. Continue to cook and when the risotto is cooked ‘al dente’, remove from the heat and serve.