1ounce semisweet or bittersweet chocolatein 4 pieces
Instructions
Microwave butter and chocolate in a large microwave-safe bowl at 50% power³ until melted, about 1 minute.
Stir in sugar, eggs, cocoa, vanilla, and salt.
Add flour and baking powder, and whisk in.
Divide the batter between 2 12-16 ounce⁴ microwave-safe mugs.
Place mugs on microwave turntable.
Microwave at 50% power for 45 seconds.
Stir batter and microwave for another 45 seconds at 50% power.
Press 2 pieces of chocolate into the center of each cake. No need to press down. They should sink in on their own.
Microwave at 50% power for 60-90 seconds.
Cake should pull away from the edge of the mug when done.
Let sit 2 minutes before serving.
Notes
Can substitute semisweet chocolate chocolate.
It's important to properly measure the flour. Either weigh the flour, or sift or stir it, lightly spoon into measuring cup, and then level. Too much flour will give you a dry or dense cake.
Microwaving at full powder will take less time. However, the chocolate will get absorbed into the cake, and you won't get a molten center.
I like to use a 16-ounce mug because it allows more room for the cake to expand. A 12-ounce mug will work, but keep an eye on it to make sure it doesn't spill over as it cooks.
Microwave wattages vary, and cooking times will vary according to the wattage.