Jar cakes are the best when you want a little dessert and are too tired or impatient (or both, like me) to make a complicated recipe. Dump some ingredients in a jar, shake, microwave. Eat.
If your coconut oil is solid add it to a pint sized mason jar and microwave for 20-30 seconds until it reaches a liquid state.
Add the other ingredients to the jar. Put the lid on and give it a good shake. Remove the lid. Microwave for 2 minutes.
To make the optional topping: In a small bowl microwave the chocolate and coconut oil until melted. Stir in the sweetener and pecans. Spoon on top of the cooked mug cake. It will be thick like a truffle.