Preheat oven to 350*. Grease 13 x 9 inch baking pan; set aside.
Sift together flour, baking powder, cinnamon, salt, allspice, ginger and nutmeg.
Beat butter in large bowl of electric mixer on medium speed until creamy. Add brown sugar; beat until fluffy. Beat in egg yolks.
Dissolve baking soda in buttermilk. Add flour mixture to butter mixture alternately with buttermilk mixture, starting and ending with flour mixture. Stir in vanilla. Pour batter evenly into prepared pan.
Prepare Meringue Frosting: Beat 2 egg whites, using clean beaters and bowl, in medium bowl of electric mixer until stiff peaks form. Gradually add brown sugar, 2 Tblsp. at a time, beating well after each addition. Beat until stiff peaks form.
Spread frosting over cake batter. Sprinkle with pecans. Bake 45 minutes or until toothpick comes out clean. Transfer to rack; let cool completely in pan.