Separately, sift the dry ingredients (flour, cocoa powder, salt, baking powder, baking soda) together
Add half of the dry ingredients, half of the cola / soda drink, mix well. Then add the remaining dry ingredients and cola and mix until you have smooth batter with no lumps.
Pour into the prepared baking pan, tap to even out the surface. Bake in the preheated oven at 160C/320F for 30-40 minutes, or until a toothpick inserted in the middle of the cake comes out clean
Let the cake cool for 30 minutes in the pan, unmold and let it cool completely. This step is super important.
Stewed Cherries or Strawberries
Make sure to used pitted or seedless cherries. You can also use strawberries with the stem removed. Add to a sauce pan with the water and sugar and mix well.
Cook on medium heat, keep stirring, smashing cherries occasionally and stewing until the mixture is thick and forms a syrup. Adjust sugar for desired sweetness. Let it cool completely in the refrigerator.
Whipped Cream Topping
Keep the whisk (just the blade part, if you're using the electric kind) and the bowl in the freezer for about 30-60 minutes. It should be very cold.
Combine cream, vanilla extract, and sugar, and whisk on low speed for a couple minutes, then increase the whipping speed, and whisk until you have stiff peaks. (Do not overmix, or you'll end up with butter!)
Make this right before you need to assemble your cake, for best results. And keep it refrigerated until you need to use it.
Chocolate Shavings
Use cheese grater or a vegetable peeler to grate the chocolate into shavings. You'll need about 1-2 cups.
Alternatively, you can also use crumbled chocolate cake for decoration
Assembling the Black Forest Cake
Carefully cut the cake into 2 or 3 layers. Place the bottom layer on a serving plate. Poke holes all over the surface with a fork.
Brush with the cherry syrup generously. Add a dollop of the whipped cream and smoothen it out. Add stewed cherries (or strawberries), sprinkle with some chocolate.
Close with the next layer, and repeat the process. Neatly frost the entire cake with the whipped cream frosting, decorate the sides with chocolate shavings or crumbled cake. Decorate on top with more cherries and chocolate.
Slice & serve immediately or keep the cake refrigerated until you need it. Use within 3-4 days.