Preheat oven to 170°C (338°F)
Mix 3 eggs with 150g sugar
Add 100ml vegetable oil [I used 20ml butter 80ml oil] and 150g plain yogurt to the mixture
Add a pinch of salt and 1 teaspoon vanilla extract
In a separate bowl, combine 200g plain flour and 1 ½ teaspoons baking powder
Fold the dry ingredients into the wet ingredients
Divide the batter into two portions
Mix 1 tablespoon cocoa powder and 1 teaspoon instant coffee with about 2 tablespoons warm water
Add the coffee-cocoa mixture to one portion of batter to create the chocolate layer
Pour the vanilla batter into the baking pan (21x11x6 cm)
Pour the chocolate batter on top
Bake for 35-40 minutes at 170°C (338°F)
Optional: sprinkle chocolate sprinkles on top before serving
