Preheat the oven to 375 degrees F.
Peel the pears and slice them lengthwise into halves. With a small sharp paring knife and a melon baller, remove the core and seeds from each pear, leaving a round well for the filling. Trim a small slice away from the rounded sides of each pear half so that they will sit in the baking dish without wobbling.
Toss the pears with some lemon juice to prevent them from turning brown. Arrange them, core side up, in a baking dish large enough to hold the pears nice and tight.
Gently toss the crumbled blue cheese, dried cranberries, and walnuts together in a small bowl. Divide the mixture among the pears, mounding it on top of the core.
In the same small bowl you used for the cheese mixture, combine the apple cider, port, and brown sugar, stirring to dissolve the sugar. Pour the mixture over and around the pears.
Bake the pears, basting occasionally with the cider mixture, for 30 minutes, or until tender.
Set aside until warm or at room temperature.
I like to serve on a platter with some butter leaves underneath for a bit of green.