Preheat the Oven: Position a rack in the center of the oven and preheat it to 325°F (162°C).
Prepare the Bundt Pan: Generously grease a 10-cup Bundt pan with shortening or butter, ensuring every nook and cranny is coated. Dust the pan with flour, tapping out any excess. Alternatively, you can use a baking spray designed for easy release to ensure effortless removal of the cake.
Prepare the Dry Ingredients: In a medium bowl, sift together the flour and baking powder; set them aside.
Prepare the Chocolate Mixture: In a separate medium bowl, whisk together half of the sugar, cocoa powder, and water until smooth; set aside.
Mix the Butter and Sugar: In the bowl of a stand mixer fitted with the paddle attachment, beat the butter at medium speed until creamy (about 2 minutes). Gradually beat in the remaining 2 cups of sugar. Increase the speed to medium-high and beat until the mixture is well-blended and light (about 4 minutes).
Add Flavor and Eggs: At medium speed, beat in the salt and vanilla. Then, beat in the eggs one at a time, mixing well after each addition and scraping down the sides of the bowl as necessary.
Combine Dry Ingredients and Milk: At low speed, add the dry ingredients in three additions, alternating with the milk in two additions. Mix just until blended.
Create Chocolate Swirl: Add the 3 cups of batter to the cocoa mixture and stir until blended.
Layer the Batters: Spoon one-third of the remaining plain batter into the prepared pan and smooth it into an even layer. Spoon one-third of the chocolate batter over the plain batter and smooth it into an even layer. Repeat with the remaining batters, alternating plain and chocolate, ending with the chocolate layer. Run a skewer or butter knife through the pan to slightly swirl the 2 batters together.
Bake the Cake: Bake the cake for 60 to 70 minutes, or until a cake tester inserted into the center comes out clean.
Cool the Cake: Cool the cake in the pan on a wire rack for 15 minutes. Invert the cake onto the rack and let it cool completely.
Assemble: Set the cooled cake on a wire rack, positioning it on parchment paper or a foil-lined baking sheet to catch any excess glaze. Slowly pour the prepared bittersweet chocolate glaze over the top of the cake, allowing it to flow naturally and drip down the sides of the cake. Ensure an even distribution of the glaze. Allow the cake to sit for approximately 30 minutes to let the glaze set and achieve a glossy finish before slicing and serving.
For the Bittersweet Chocolate Glaze:
Prepare the Glaze Ingredients: Place the chocolate in the bowl of a food processor and process it until finely ground. Leave the chocolate in the food processor.
Heat the Cream: In a small saucepan, bring the cream to a boil. Remove it from the heat and add the chocolate to the food processor. Process until the chocolate is completely melted and smooth. Stir in the vanilla extract.
Transfer and Cool the Glaze: Transfer the glaze to a small bowl. Cover the surface of the glaze with a piece of plastic wrap and let it cool for 10 minutes before using.
Camila's Tips: The glossy glaze may become dull and slightly hard when chilled, so be sure to bring the cake back to room temperature before serving.