Preheat oven to 350 degrees. Butter a 9-inch pie plate; set aside. Peel, halve, and core the pears. Slice the pears lengthwise 1/4-inch-thick. Arrange pear slices in baking dish in a slightly overlapping circular pattern; set aside.
In a blender, process, butter, milk, granulated sugar, flour, vanilla, eggs, and salt, until smooth.
Pour batter over pears and bake until golden, and firm to the touch, 40 to 45 minutes. Serve warm or room temperature dusted with confectioners' sugar.