FOR CRUST: Position rack in center of oven and preheat to 350 deg. Butter 9-inch-diameter deep-dish glass pie dish. Combine graham cracker crumbs and sugar in medium bowl. Add melted butter and stir until well incorporated. Press graham mixture evenly into bottom and up sides of prepared dish. Bake until crust is set, about 5 minutes. Cool on rack. Maintain oven temperature. FOR FUDGE LAYER: Sift flour, baking powder and salt into medium bowl. Combine butter semisweet chocolate and unsweetened chocolate in top of double boiler set over simmering water. Stir until melted and smooth. Remove from over water and cool slightly. Using 05/29 11:18 pm Don Fifield -Marietta, GA yolk in medium bowl until slightly thickened, about 1 min. Add vanilla and cooled chocolate mixture and mix until well blended. Add dry ingredients and mix just until combined.