Stuffed Fennel with Reblochon Sauce light and fragrant

Wash the fennel bulbs. Cook them for 15 to 20 minutes in a pot of boiling salted water (they should be tender while maintaining their structure). Drain them, let cool slightly, then cut them in half lengthwise. Remove and chop the flesh from each half bulb.
Cut the escalopes into small pieces and chop them with the sage leaves, season with salt and pepper, mix with the chopped fennel and set aside. Bring the water to a boil with the chicken stock cubes.
In a saucepan, melt 1.1 oz (30 g) of butter over low heat. Incorporate the flour while stirring constantly. Gradually pour in the chicken stock. Add the liquid crème fraîche and half of the reblochon. Cook for 5 to 6 minutes, stirring constantly.
Sauté the onions with the lardons in a pan without adding any fat. Incorporate the fennel and escalope mixture. Distribute the preparation in the hollowed-out fennel bulbs. Place them in a gratin dish. Spread the reblochon sauce over them, place the remaining reblochon cut into pieces on top and gratinée for 10 to 12 minutes in a preheated 355°F (180°C) oven.