This recipe produces moist, tender, fluffy, cinnamon and vanilla butter cake with a signature cinnamon sugar crust. After biting it, you may think, "This is serious cake, not just 'mug cake'."
Measure the buttermilk into a microwave safe container, add butter, and microwave on HIGH until the butter is melted into the buttermilk. Remove from the microwave, stir in the vanilla extract and set aside.
Whisk the flour, sugar, cinnamon, baking powder, and kosher salt together (or use a fork to combine) in a small bowl. Add the buttermilk mixture and use a fork or small whisk to combine just until smooth. Scrape into a microwave safe mug, sprinkle with the cinnamon sugar, and microwave on HIGH for 2 minutes 10 seconds. This is best eaten warm.
Nutritional information is an estimate and provided to you as a courtesy. You should calculate the nutritional information with the actual ingredients used in your recipe using your preferred nutrition calculator.