Steps
1. In a small mixing bowl, combine whole wheat flour, sugar, baking powder, baking soda, and salt.
2. In another bowl, whisk together yogurt, milk, vegetable oil, and vanilla extract until smooth.
3. Gradually add the wet ingredients to the dry ingredients, stirring gently until just combined. Avoid overmixing.
4. Grease a small microwave-safe mug or ramekin.
5. Pour the batter into the prepared mug.
6. Microwave on high for 90 seconds. Check doneness by inserting a toothpick; if it comes out clean, the cake is ready. If not, microwave for an additional 15-20 seconds.
7. Let it cool slightly before enjoying directly from the mug or turning out onto a plate.