Preheat the oven to 325°F. Choose a shallow, lidded pan that will accommodate the endives with little room to spare.

Melt the butter until just about to turn nut brown. Add the endives and turn down the heat. Season with salt and pepper and turn gently in the butter from time to time to coat all the surfaces and to color them lightly.

Add the lemon juice, allow the endives to bubble, put on the lid, and cook in the oven for 2 hours.

Halfway through the cooking, carefully turn each one over. The endives should be very soft and limp, the lemon juice completely evaporated, and the end result buttery and golden.