This recipe makes one medium/large mug cake but can easily be halved for a smaller treat. Add the butter to a medium sized microwave-safe mug and microwave for 10-20 seconds or until melted. (If using oil instead of butter, skip this step)
Add the vanilla extract, brown sugar, and white sugar to the mug and mix them together with the butter.
Add in the flour, cocoa powder, salt, and baking powder, then mix in the milk. Mix well with a fork or spoon until no lumps remain. Stir in chocolate chips if using.
Microwave the mug cake for 45-65 seconds. The exact time will depend on your microwave. The top of the cake should look a little bit shiny, and not quite cooked on top. Be sure to not over-cook it or it will be dry!
Let it cool for a couple minutes, then top with ice cream, whipped cream, or nut butter, if desired. The mug cake should be eaten immediately.
Preheat the oven to 350°F.
Melt the butter or coconut oil over the stove (or, for a quicker method with less dishes, skip this step and use canola oil)
Add butter or oil to a oven-safe mug, ramekin (3.5 - 4 inches), or bowl, then use a fork to mix in the sugars and vanilla extract.
Add in the flour, salt, baking powder, and cocoa powder, then and the milk. Mix until no clumps remain and no bits of flour are left in the bottom of the dish. Stir in the chocolate chips if using.
Place in the oven and bake for 22-26 minutes or until a toothpick inserted in the middle comes out clean. Be careful removing the dish from the oven! Let it cool for 5 minutes then enjoy!
BUTTER: You can use melted butter, canola/vegetable oil, or melted coconut oil at a 1-1 substitution ratio.FLOUR: Whole wheat flour, oat flour, or gluten free 1-1 baking flour can be substituted at a 1-1 ratio.COCOA POWDER: You can use any kind of unsweetened cocoa powder for this recipe.SUGAR: You can replace all of the granulated and brown sugar with coconut sugar or maple syrup for a refined sugar free version. MUG SIZE: If the mug is too small, the cake batter will spill over the sides in the microwave, so I recommend using a regular sized (but not too large) coffee mug. If using the oven method, the cake will rise slowly, so you can use a 3.5 or 4 inch ramekin if desired.MICROWAVE: Microwave times vary greatly! You can start at 40 seconds and go up from there until the mug cake is cooked. The top will still look a little bit wet but it's better to under-cook than over-cook it. Storage Instructions:Microwave Method: If you make this mug cake in the microwave, it should be enjoyed immediately once cooled. As with most food that gets microwaved, it will start to dry out if left out for a few hours.Oven Method: If you use the oven method, the mug cake can be tightly covered with plastic wrap or aluminium foil and stored at room temperature for a few hours, up to one day.