where ever you go, call ahead, and have them bake you a special cake with 'Will you marry me?' on it. Make sure the waiter/manager knows whats going on so they'll be no screw ups.
if they can't bake you a special cake, have them bring out some other dessert she likes on a large plate where the chef can write 'will you marry me?' on the plate around the dessert.
its sorta cheesy, but it worked for me