Preheat the oven to 350 degrees F. Lightly grease a 9-inch baking dish with butter and set aside.
In a bowl, toss the pear slices with the lemon juice. Add 1 tablespoon flour, the sugar, and port, and toss to combine. Arrange in the prepared dish. In a bowl, combine the remaining 1/2 cup flour, finely chopped walnuts, brown sugar and salt. Add the butter, working in with your fingertips until it resembles coarse crumbs. Sprinkle over the pear mixture. Bake until the pears are tender, the juices bubble, and the crust is golden, 40 to 45 minutes.
Remove from the oven and sprinkle the cheese over the top. Cook until the cheese is melted, about 5 minutes. Remove from the oven and let sit for 10 minutes before serving.
Yield: 6 to 8 servings