Preheat oven to 350°.
Spread softened butter evenly into the bottom of an 8-inch round cake pan, and sprinkle with brown sugar and walnuts. Set prepared pan aside.
Combine milk and bread in a large bowl. Let stand 15 minutes, occasionally pressing on bread to soak up milk. Add 1/2 cup granulated sugar, melted butter, vanilla, salt, and eggs; stir with a wooden spoon 1 minute or until bread cubes break apart. Stir in raisins, cognac, and 1/2 teaspoon grated rind. Pour bread mixture into prepared pan. Place pan in a 13 x 9-inch baking pan; add hot water to larger pan to a depth of 1 inch. Bake at 350° for 50 minutes or until a knife inserted in center comes out clean. Remove cake pan from water. Let stand 5 minutes. Invert onto a serving platter.
Sift 2 tablespoons granulated sugar evenly over pudding. Holding a kitchen blowtorch about 3 inches from surface of pudding, heat sugar, moving torch back and forth, until sugar is completely melted and caramelized (about 1 minute). Serve warm. Garnish with orange rind strips, if desired.