1. After cutting the chard, use the most tender part, cut it into small pieces, and clean it with lemon water to avoid browning, then cook it in a large quantity of salted water for 30 minutes. Drain well and pass through a vegetable mill, then put everything in a bowl.
2. In a frying pan, heat the olive oil with the butter. Sauté the shallot with salt for 2 minutes.
3. Add the chard puree, mix well and cook for 10 minutes. Add the milk, which has been slightly warmed in a small saucepan, and the Fontina cheese, cut into cubes. Continue stirring with a wooden spoon and continue cooking over medium heat until the preparation is creamy.
4. In a large quantity of salted water, cook the agnolotti pasta al dente. Drain well and put in the frying pan with the chard cream, add grated Parmesan and mix well. Heat the agnolotti for a few minutes.
5. Transfer to a serving dish and serve immediately.