Heat the olive oil and butter in a large pan or Dutch oven over medium heat. Add the sliced fennel and cook for about 5-7 minutes, stirring occasionally, until the fennel starts to soften.
Add the chopped onion and minced garlic to the pan. Cook for another 3-4 minutes until the onion becomes translucent.
Stir in the Arborio rice and cook for 1-2 minutes, stirring constantly, until the rice is well coated with the oil and butter mixture.
Pour in the white wine and cook, stirring frequently, until the wine has been absorbed by the rice.
Begin adding the warm broth to the rice mixture, one ladleful at a time, stirring constantly and allowing each addition to be absorbed before adding more. Continue this process until the rice is creamy and cooked al dente, which should take about 18-20 minutes.
Once the risotto is cooked to your desired consistency, remove it from the heat. Stir in the freshly grated Parmesan cheese, and Italian Volcano lemon juice. Season with salt and black pepper to taste.
Taste the risotto and adjust seasoning if necessary.