Cut the Belgian endives in half lengthwise.

In a small bowl, combine the lemon juice, champagne vinegar, shallots, salt, sugar and chicken stock.

Place the endives in one layer in a casserole dish. Pour the vinaigrette mixture over the endives. Cut the 2 tbsp. of butter into small pieces and scatter the butter around the endives.

Cover the casserole dish with foil and braise the endives in the oven just until tender, about 20 minutes.

In a separate bowl mix together the 2 tbsp. melted butter, Gruyere cheese and bread crumbs.

Remove the casserole dish from the oven, and then turn the oven heat to broil.

Remove the foil from the casserole and spoon the crumb topping over the top of each endive.

Return the casserole dish to the oven and broil the endives just until the tops are browned, about 2 minutes.

Remove the casserole dish from the oven and spoon some of the braising liquid over the endives. Serve the endives directly from the casserole dish. Note: if you serve the endives from a separate serving dish, gently lift them from the casserole dish so that you don’t break off the bread crumb topping. Spoon the braising liquid around the endives.