German Chocolate Cake

Grease sides of two 9-inch (1.5 L) or 8-inch (1.2 L) round cake pans; line bottoms with parchment or waxed paper. Set out 2 rimmed baking sheets. Set all pans aside.

In heatproof bowl set over saucepan of hot (not boiling) water, melt chocolate with water, stirring until smooth; let cool to room temperature, about 30 minutes.

In large bowl, beat butter with sugar until light and fluffy. Beat in eggs, 1 at a time, beating well after each. Mix in vanilla and chocolate mixture.

In separate bowl, whisk together flour, baking powder, baking soda and salt. With wooden spoon, stir into butter mixture alternately with sour cream, making 3 additions of dry ingredients and 2 of sour cream. Scrape into prepared pans; smooth tops.

Bake in centre of 350°F (180°C) oven until cake tester inserted in centre comes out clean, about 35 minutes. Let cool in pans on racks for 10 minutes. Turn out onto racks; peel off paper. Invert; let cool. (Make-ahead: Wrap in plastic wrap and store at room temperature for up to 1 day or overwrap in heavy-duty foil and freeze for up to 1 month.)

Filling: Arrange pecans and coconut separately on baking sheets. Toast in 350°F (180°C) oven, stirring once, until coconut is golden and pecans are darkened, 6 to 7 minutes for coconut, 8 to 9 minutes for pecans. Transfer to large bowl; let cool.

Meanwhile, in saucepan, whisk together sugar, milk and egg yolks; cook, stirring, over medium heat until thick enough to coat spoon thickly, 5 minutes. Stir in butter and vanilla; remove from heat. Add to pecan mixture; stir until butter is melted. Refrigerate until cold and thickened enough to spread without running, about 2 hours. (Make-ahead: Cover and refrigerate for up to 1 day.)

Ganache Icing: Place chocolate, butter and corn syrup in heatproof bowl. In saucepan, bring cream just to boil; pour over chocolate, whisking until melted and smooth. Let cool to almost room temperature.

Brush loose crumbs from cake layers. Cut each layer in half horizontally. Place
1 cake layer, cut side up, on flat cake plate; slide 4 strips of waxed paper between cake and plate. Spread with one-third of the filling, spreading right to edge. Repeat to make second and third layers; top with remaining layer, cut side down.

Brush off any loose crumbs. Spread about one-third of the icing over top and side of cake to mask. Refrigerate until firm, about 30 minutes.

Meanwhile, stir the icing occasionally to keep spreadable. Spread remaining icing (it should be room temperature and slightly thickened) smoothly over cake. Remove paper strips. Refrigerate until firm, 1 hour. (Make-ahead: Cover and refrigerate for up to 1 day.)