The restaurant overlooking the Royal Skating Rink (not much in use now) is set in the large park/wood called Bois de la Cambre. In the warmer months, be sure to reserve a table outside; in the winter the cosy tartan interior is equally accommodating. The food is great and the old-school service probably the best in Brussels. More on the expensive side but worth it.
Rue Veydt 15, Brussels, Belgium