20-25gcaster sugar (depending on your sweet tooth)
1.5g(scant 1/2 teaspoon)baking soda (not baking powder)see notes
25gthick plain yoghurt (I used Jalna Lactose free Greek)
40ml(2 tablespoons)*milk of choice (I used lactose free full cream)USA, NZ and Canadian users: 40ml is roughly 2 1/2 tablespoons in your measurements
25gbutter, melted
10ml(2 teaspoons)vinegar or lemon juice
1/2 teaspoonvanilla bean paste or extract (optional)
Instructions
Whisk together the dry ingredients in a small bowl. Whisk in the wet ingredients until a batter forms. Once it has, whisk for an additional 10-15 seconds until the batter thins slightly.
Decant the mixture into a large heatproof mug. Cook for 1 minute or until the mug cake is firm yet springy to the touch. The timing will depend on your individual microwave.
Allow to cool for a minute or two before serving. I like to top mine with some ice cream and sprinkles, but anything goes.
Notes
It is super important to be precise with your baking soda measurement. Adding too much will result in a salty metallic taste to your mug cake.
Use unsweetened plant based yoghurt, milk and butter for a dairy free/vegan version.