- With the rack in the middle position, preheat the oven to 400°F (200°C). Line a baking sheet with a few layers of paper towel.
- In a large skillet, bring all the ingredients to a boil. Season with salt and pepper. Cover and let simmer over low heat for 15 minutes or until the endives are tender. Check their tenderness by inserting a toothpick into the centre. If it slides in easily, the endives are cooked.
- Meanwhile, in a small pot over medium heat, melt the butter. Whisk in the flour and cook for 1 minute. Whisk in the milk. Bring to a boil and let simmer gently for 2 minutes or just until the sauce has thickened. Add the nutmeg. Season with salt and pepper. Remove from the heat and cover.
- With a slotted spoon, remove the endives from the cooking liquid. Drain on the paper towels. Cover with a cloth or paper towels and press lightly to extract as much liquid as possible. Discard the cooking liquid.
- In an 11 x 8-inch (28 x 20 cm) baking dish, lay out the drained endives. Cover with the béchamel sauce and sprinkle with the cheese.
- Cook in the oven for 20 minutes or until the cheese has melted and is slightly golden. Sprinkle with the bacon and chives. Let cool for 15 minutes before serving.