Mushroom and Spinach Risotto

1. In a large pot or Dutch oven, heat olive oil and butter over medium heat. Add chopped onion and cook until softened, about 3-5 minutes. 2. Add sliced mushrooms and cook until browned and their liquid has evaporated, about 5-7 minutes. 3. Stir in the Arborio rice and cook for 1-2 minutes until the edges are translucent. 4. Pour in the white wine and stir until it's completely absorbed by the rice. 5. Begin adding the warm vegetable broth, one ladleful at a time, stirring constantly and allowing each addition to be absorbed before adding the next. This process will take about 20-25 minutes. 6. Once the rice is creamy and al dente, stir in the fresh spinach until it wilts. 7. Remove from heat and stir in the grated Parmesan cheese. Season with salt and pepper to taste. Serve immediately.