Combine first 4 ingredients; add crystallized ginger, tossing to coat. Set aside.
Process butter and sugars in a food processor 1 minute.
Add eggs, 1 at a time, through food chute with processor running; process just until mixture is blended. Scrape down sides of bowl, if necessary; add brandy, grated orange rind, and orange juice. Gradually add dry ingredients through food chute, pulsing 3 to 4 times or just until blended.
Pour batter into a greased 8-cup fluted pudding mold, and cover tightly with greased aluminum foil. Place mold on a small wire rack in an 8-quart Dutch oven; add enough hot water to Dutch oven to come two-thirds up sides of mold. Bring water to a boil; cover, reduce heat, and simmer 1 1/2 hours, adding additional hot water as needed. Serve with Lemon Sauce. Garnish, if desired.
* 1 cup all-purpose flour may be substituted.
** 1 (2.7-ounce) jar crystallized ginger and 1/2 cup golden raisins, finely chopped, may be substituted.