Preheat the oven to 180C/350F and line the base of a baking tin with parchment paper.
Whilst the oven heats, toss the pecans into a baking tray in an even layer and toast for until lightly golden, approximately 5 minutes.
Remove and set aside.
Place the eggs, sugars, buttermilk and sunflower oil into a bowl and combine with a whisk until the eggs are broken up and smooth.
In a small separate bowl, place the coffee, boiling water and cocoa powder and whisk until smooth.
Pour into the buttermilk mixture and whisk to combine.
In a separate bowl, place the flour, baking powder, baking soda and salt and stir to combine with a fork (this will help remove large lumps).
Add the dry ingredients into the wet ingredients and combine until your batter is smooth and no dry ingredients remain on the sides of the bowl.
Divide the batter evenly (weighing this will help you create equal portions) into your 4 cake tins and bake for 25 minutes or until a skewer comes out clean.
Remove and allow to cool before removing from the tin.
Turn onto a cooling rack to cool completely.