In a medium bowl combine cocoa with boiling water. Mix until smooth. Cool completely.
In another bowl, sift flour with baking soda, baking powder and salt. Preheat oven to 350 degrees F.
Grease and lightly flour three 9" x 1 1/2" layer cake pans. In another large bowl, with electric mixer at high speed, beat butter, sugar, eggs and vanilla until light (about 5 minutes), scraping bowl occasionally.
At low speed, beat in flour mixture (in fourths) alternately with cocoa mixture (in thirds), beginning and ending with flour mixture. Do not overbeat. Divide batter evenly into prepared cake pans. Smooth top. Bake 25-30 minutes or until surface springs back when gently pressed with fingertip. Cool 10 minutes. Carefully loosen sides with spatula, remove from pans, cool completely on wire racks.
In medium saucepan, combine chocolate pieces, cream and butter; stir over medium heat until smooth. Remove from heat. With whisk, blend in 2 1/2 cups confectioners sugar. Set mixture on top of another bowl filled with ice, beat until frosting holds its shape.
Whip cream with confectioners sugar and vanilla until smooth. Place in refrigerator 20 minutes.
On plate, place a layer, top side down; spread with half of cream filling. Place second layer, top side down, on top of first layer and spread with remainder of cream filling. Place third layer, top side down, on top of second layer.
With spatula, frost sides first, covering with whipped cream filling. Frost top with remaining frosting, swirling decoratively. Refrigerate at least 1 hour before serving. To cut, use a thin-edged sharp knife with a sawing motion.
Line 3 (9-inch) round cakepans with wax paper; lightly grease and flour wax paper. Set pans aside. Stir together first 4 ingredients. Beat eggs and next 4 ingredients at medium speed with an electric mixer until smooth. Add flour mixture, beating at low speed until blended. Fold in carrot and next 3 ingredients. Pour batter into prepared cakepans. Bake at 350° for 25 to 30 minutes or until a wooden pick inserted in center comes out clean. Drizzle Buttermilk Glaze evenly over layers; cool in pans on wire racks 15 minutes. Remove from pans, and cool completely on wire racks. Spread Cream Cheese Frosting between layers and on top and sides of cake.
Beat sugar and butter at medium speed with a heavy-duty electric stand mixer until creamy and fluffy (about 5 minutes). Add eggs, 1 at a time, beating until yellow disappears after each addition. Beat in vanilla bean paste and almond extract. Whisk together flour, baking powder, and salt in a small bowl; add to sugar mixture alternately with buttermilk, beginning and ending with flour mixture. Beat at medium-low speed just until blended after each addition. (Batter will be thick.) Bake at 350° in 2 greased and floured (8-inch) square pans 30 to 34 minutes. Cool as directed
Melt butter in 2-quart saucepan. Stir in brown sugar, evaporated milk and salt. Bring to a boil, stirring constantly. Remove from heat; cool to lukewarm. Add powdered sugar; beat until frosting is of spreading consistency. Add vanilla; beat until smooth.