This chocolate marble yogurt cake requires no mixer to make it and best eaten warm with a scoop of ice cream! Double the recipe to bake the cake in a loaf tin (8 x 4-inch) or a 7-inch round tin, or use my cake pan converter if you have a different cake pan!
Preheat oven to 175 degrees Celsius. Grease the sides and bottom of the cake tin and line the bottom with baking parchment. Set aside.
In a small bowl, stir cocoa powder and hot water together until cocoa has dissolved. Set aside.
Measure sugar, yogurt, oil, egg and vanilla directly into a large mixing bowl and whisk together until incorporated.
Sift in flour, baking powder, baking soda and salt and whisk in gently until just incorporated. Use a spatula and scrape the sides and bottom of the mixing bowl to make sure all the flour mixture is incorporated.
Scoop ⅓ of the cake batter into the small bowl of cocoa mixture and stir gently until well-mixed.
Spoon 2 spoonfuls of vanilla cake batter into the prepared cake tin then spoon in 1 spoonful of chocolate cake batter. Repeat until all the batter has been used up. Insert a skewer and swirl through the batter a few times (without removing the skewer until the end) to create a marble effect. Bake for 40 to 45 minutes until a skewer inserted into the center of the cake comes out clean. If the top is browning too fast, tent it with a piece of aluminum foil.
Place the cake tin on a wire rack and let the cake cool completely. Run a spatula along the sides of the cake tin and turn out the cake. Peel off the baking parchment and turn the cake right side up and transfer to a serving dish. Dust with icing sugar and cocoa powder if desired and serve.
Make sure the ingredients are at room temperature before mixing them together - take them out of the refrigerator and place on the table counter for 30 minutes before using.
For the yogurt, you can use Greek or non-Greek, plain or flavoured, full-fat or low-fat - it's entirely up to you.
For the oil, you can use extra-virgin olive oil, canola oil, vegetable oil, coconut oil or any nut oil.