Ingredients:

  • 4 tbsp all-purpose flour
  • 2 tbsp Dutch-processed cocoa powder
  • 3 tbsp granulated sugar
  • 1/4 tsp baking powder
  • 1 pinch fine sea salt
  • 1 large egg
  • 3 tbsp whole milk
  • 2 tbsp neutral oil
  • 1/2 tsp vanilla extract
  • 1/4 tsp instant espresso powder
  • 1 large piece dark chocolate (70% cacao)

Instructions:

  1. Whisk dry base. Place the flour, cocoa powder, sugar, baking powder, salt, and espresso powder into your mug. Note: Mixing these first prevents the cocoa from clumping once wet.
  2. Combine wet ingredients. Crack the egg into the mug and add the milk, oil, and vanilla extract.
  3. Emulsify the batter. Use a fork to beat the mixture until no dry streaks remain and the batter looks glossy.
  4. Insert the core. Take that large piece of dark chocolate and push it right into the center of the batter. Note: Don't push it all the way to the bottom or it might stick.
  5. Clean the rim. Wipe any splashes off the inside rim of the mug with a paper towel. This prevents burnt bits from forming.
  6. Pulse the cook. Microwave on high for 60 seconds. Watch for the cake to rise and the surface to look matte.
  7. Check for doneness. The edges should be set, but the very center should still look slightly damp.
  8. Rest the cake. Let the mug sit in the microwave for 1 minute before touching it. Note: This carryover cooking finishes the center gently.
  9. Serve warm. Grab a spoon and dive in while the chocolate center is still liquid.