Cube & weigh/measure out your 225 grams Unsalted Butter & leave to soften. Cubing small to about 1cm (⅓") gives a smaller surface area that softens quicker.
Add the 225 grams Castor Sugar to the softened butter & beat together, (with a hand-mixer or stand-mixer), 'creaming' for about 3-5 minutes until very creamy, smooth & also paler in colour. Add in the 4 Eggs one at a time with the mixer on low to medium speed, mixing in-between each addition.
Sieve over the 175 grams Self-raising Flour (& 3⅛ tsp baking powder if using plain/A.P. flour) & the 50 grams Cocoa Powder. Mix briefly by hand and leave to the side.
Heat up the oven to: 170°c/150°c Fan oven/325°f/Gas Mark 3. Add 2½ tbsp Hot/Boiled Water to the bowl of 2½ tsp Chai Latte powder & ¾ tsp Coffee granules/espresso powder & mix till dissolved. (*Use a total of 1¾ tsp coffee if not using Chai Latte powder). Add the coffee mixture to the cake batter and mix just until everything is combined and no dry flour/cocoa patches remain. *Do not over-mix*.
Grease your cake tins well, on the bottom & up the sides. Place a circular piece of baking/parchment paper on the bottom of the tin. I recommend using Frylight cooking spray or homemade greasing/lining paste recipe. Spoon the cake batter evenly between the two tins & smooth out best you can. Place the 2 tins in the middle shelf of the oven and bake for about 20 - 25 minutes. A wooden cocktail stick should come out clean of crumbs & the cakes be coming away from sides of the tin.
Leave to cool in the tins, on a cooling rack for 10 minutes, before releasing from the tins, removing the paper and leaving to cool for at least 15 minutes.