When beating such a small amount of egg white (you only need one) to soft peaks, it's easy to do by hand. Just place the white in a medium bowl, and beat vigorously with a whisk; it should take about a minute.
Preheat oven to 400°.
Place cranberries in a small bowl; cover with boiling water. Let stand 10 minutes; drain.
Weigh or lightly spoon flour into a dry measuring cup; level with a knife. Combine flour, 1/3 cup sugar, and 1/8 teaspoon salt.
Whisk together milk, cream, liqueur, 2 eggs, and 1 yolk.
Gradually sift flour mixture into milk mixture, whisking until smooth. Fold in egg white. Set aside.
Heat a 10-inch ovenproof skillet over medium-high heat. Add butter; swirl until butter melts. Add pear; sauté 3 minutes.
Remove skillet from heat. Pour batter evenly over fruit mixture.
Bake at 400° for 14 minutes or until lightly browned and a toothpick inserted in center comes out mostly clean. Let stand 10 minutes before serving.
Garnish warm clafoutis with powdered sugar, blue cheese, and walnuts.