Melt the butter. Place the butter in a microwave-safe mug and zap for 20–30 seconds until melted. Don’t wander off—burnt butter is sad butter.
Add sugar and egg. Stir in the sugar and crack in your egg. Mix until smooth. This is your chocolatey base!
Mix in dry ingredients. Add cocoa powder, flour, and a pinch of salt. Stir well, making sure there are no stubborn lumps hiding in the corners.
Flavor boost. Drop in the vanilla extract and give one last stir. Your mug is now basically a chocolate volcano waiting to erupt.
Microwave magic. Zap on high for 60–75 seconds. Timing can vary based on your microwave, so start with a minute and add 10-second increments if needed. The top should look set, but the center remains molten.
Optional toppings. Sprinkle chocolate chips on top or add a dusting of powdered sugar. A scoop of ice cream? Chef’s kiss.
Serve immediately. The lava doesn’t wait. Grab a spoon and dig in while it’s still warm and gooey.