Combine 1 cup flour, sugar, undissolved yeast, and salt in large mixer bowl. Place milk, water, butter, unsweetened and semisweet chocolate in microwave-safe bowl. Microwave on HIGH (100%) 2 to 2-1/2 minutes, stirring every 30 seconds until chocolate melts and temperature reaches 120o to 130oF. Stir into flour mixture. Beat 2 minutes at medium speed of electric mixer, scraping bowl occasionally. Add egg and 1/2 cup flour; beat 2 minutes at high speed. Stir in enough remaining flour to make soft dough. Knead on lightly floured surface until smooth and elastic, about 8 to 10 minutes. Cover; let rest 10 minutes.
Divide dough into 12 pieces. Roll each piece into 8 x 4-inch oval. Spread Chocolate Filling evenly over each oval. Beginning at short end, roll up tightly. Pinch seams to seal. Place rolls, seam sides down, on parchment-lined or heavily greased baking sheets. With kitchen scissors or sharp knife, make 5 slits on top of each roll, cutting halfway through. Curve ends to form crescents. Cover; let rise in warm, draft-free place until doubled in size, about 1 hour.
Bake at 375oF for 15 to 20 minutes or until done. Remove from sheet; cool on wire rack. Sprinkle with powdered sugar.
Chocolate Filling: Combine sugar, cocoa powder, and flour in small bowl. Cut in butter with pastry blender or fork; blend well. Stir in 1 egg; add pecans. Stir well.