- 8 tablespoons butter, plus extra for greasing the mugs
- 3 tablespoons flour, plus extra for flouring the mugs
- 1/2 cup sugar, plus extra for coating the mugs with sugar
- 10 ounces semi-sweet chocolate chips
- 4 large eggs
- 1 large egg yolk
- 1 teaspoon vanilla extract
- 1/4 teaspoon salt
- 1/2 cup mini marshmallows
- 1 tablespoons unsweetened cocoa powder (optional)
- Preheat oven to 375. Generously butter 8 six ounce mugs. Put a little flour into each one and shake it around until the flour sticks to the butter. Repeat with a little sugar.
- Put the 8 tablespoons of butter and the chocolate chips into a double boiler or a bowl over simmering water until the chocolate is melted, stirring every now and then. Set the bowl aside to cool while you do the next step.
- Use a mixer to beat eggs, yolk, vanilla, 1/2 cup sugar and salt on medium high speed for 5 minutes.
- Stir the 3 tablespoons of flour into the chocolate. Now slowly add the chocolate mixture to the to the egg mixture, beating on low until everything is fully combined.
- Spoon the hot chocolate batter into each cup until it is almost but not quite full. Put the mugs on a rimmed baking sheet and bake for 15 minutes – the cake will be a little puffy.
- Remove the tray from the oven and cover each cake with marshmallows. Put the tray back in the oven until the marshmallows start to turn golden and puffed, about 3 minutes or so.
- Shake a little cocoa powder on top, cool for a few minutes and serve them up!