This recipe from America's Test Kitchen supersedes the previous mug cake recipe; the more broken-up cooking process with intermediate stirring results in a more moist, even cake.

Molten Chocolate Microwave Mug Cake

The Perfect Cake, p.86

Ingredients

• 4 tbsp butter
• 1 oz (30g) bittersweet chocolate, chopped
• ¼ C sugar
• 2 large eggs
• 2 tbsp cocoa
• 1 tsp vanilla extract
• ¼ tsp salt
• ¼ C flour
• ½ tsp baking powder
• 1 oz (30g) bittersweet chocolate, divided into 4 equal pieces

Directions

1. Microwave butter and chopped chocolate in a large bowl at 50% power until melted.
2. Whisk in sugar, eggs, cocoa, vanilla, and salt.
3. In a separate bowl, combine flour and baking powder; whisk into chocolate mixture.
4. Divide batter evenly between two coffee mugs.
5. Place both mugs in the microwave and cook at 50% power for 45 seconds.
6. Stir and return to microwave for another 45 seconds at 50% power.
7. Press two chocolate pieces into the top of each mug.
8. Microwave for another 30-60 seconds; chocolate pieces should be melted and cake slightly wet around the edges.
9. Let stand 2 minutes before serving.