Chocolate Slab Cake with Chocolate Fudge Frosting

Step 1

Preheat your oven to 350°F (175°C). Grease and line a 9 x 13 pan with parchment paper.

Step 2

In a large mixing bowl, sift together the all-purpose flour, cocoa powder, baking soda, baking powder, and salt using a mesh strainer. Sifting helps to ensure that the dry ingredients are well combined and free of lumps.

Step 3

Add brown sugar, white sugar and coffee granules to dry ingredients. Use a hand whisk to thoroughly combine all of the dry ingredients. This helps to evenly distribute the leavening agents and sugar, ensuring a uniform texture in your cake.

Step 4

In a separate bowl, whisk together the milk, vegetable oil, vanilla extract, and eggs. Ensure that the wet ingredients are well combined.

Step 5

Create a well in the centre of the dry ingredients. Pour the wet ingredients into the well. Gently fold the dry ingredients into the wet ingredients until just combined.

Step 6

Gradually add the hot water to the batter, stirring continuously. The batter will be thin, but this is normal. The hot water helps to bloom the cocoa and create a moist cake.

Step 7

Continue to mix the batter until it becomes smooth. The consistency should be thin but well-mixed.

Step 8

Pour the batter evenly into the prepared cake pan. Tap the pan on the counter to release any air bubbles.

Step 9

Place the pan in the preheated oven and bake for 40-45 minutes or until a toothpick inserted into the centre comes out clean.

Step 10

Allow the cake to cool in the pan for 20 minutes before transferring it to a wire rack to cool completely.

Step 11

Once the cakes are completely cool, you can frost them with your favorite frosting or serve them as-is.

Step 12

In a medium-sized pan over medium heat, combine the chopped chocolate, unsalted butter, powdered sugar (if using), vanilla, instant coffee granules (if using), cream and a pinch of salt.

Step 13

Stir the ingredients continuously with a wooden spoon or silicone spatula until the chocolate and butter are completely melted and the mixture is smooth. The sugar, if used, should dissolve into the mixture.

Step 14

Mix until the mixture is well combined and has a glossy texture.

Step 15

Once the mixture is smooth and well combined, remove the pan from the heat.

Step 16

Transfer the frosting to a mixing bowl. Let it come to room temperature then refrigerate and allow it to chill until it reaches a spreadable yet thick consistency.

Step 17

Once the frosting has reached the desired consistency, spread it generously over the cooled chocolate cake with an angled spatula.

Step 18

If desired, you can decorate the frosted cake with additional chocolate shavings, sprinkles, or other decorations of your choice.