Chocolate Birthday Cake Recipe

1. Make the cake: Preheat oven to 350°F (180°C). Line a 9*13-inch (23*33cm) baking pan with parchment paper then spray with cooking spray. Set aside.
2. In a large bowl mix flour, cocoa powder, sugar, baking powder, baking soda and salt. Set aside.
3. In a separate bowl, whisk eggs, oil, buttermilk and vanilla extract. Whisk until combined and smooth.
4. Add the wet ingredients to the dry ingredients and mix until combined. A a small bowl or a mug whisk hot water with instant coffee, pour in the coffee into the cake batter and mix until combined.
5. Pour the batter into prepared pan and bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean.
6. Allow to cool completely before frosting.
7. Make the frosting: place chocolate and butter in a heatproof bowl, set the bowl over a pot with simmering water (double boiler) and melt completely. You also can melt it in the microwave (30 second pulses). Add powdered sugar, cocoa powder, vanilla extract and milk. Whisk until combined.  
8. Frost the cake as desired, decorate with sprinkles.
9. Refrigerate for at least 1 hour before serving.

Notes:

• If you don't like strong chocolate flavours in the frosting reduce the amount of cocoa powder to 1 tablespoon or don't use in at all.
• You won’t feel the coffee, but it helps bring out chocolate flavor. If prefer not to use coffee, use same amount of water.
• You can prepare the cake a day ahead.
• If the frosting is too sweet to your taste, use less powdered sugar.