Tried this yesterday and it was quick and quite good ...

1/4 cup almond flour ( I only had ground almonds, so used that)
1T Cocoa powder
1/4 t baking powder
4-5 packets Splenda

2T melted butter
1T water, or SF syrup ( I used DaVinci choc)
1 egg

In a 2 cup pyrex measuring cup, mix all the dry ingredients. Mix the melted butter with the egg and the SF syrup ~ add to the dry ingredients. Mix thoroughly. Cover with plastic wrap ... make small slit in wrap, with a knife to vent. Microwave on high for about 1 minute, 10 sec. Adjust as needed for your micro. When it comes out it looks a bit wet, but drys as it cools. ( I do not have a two cup measure, so I pit it in two little glass bowls, and it worked fine)

You can eat warm like a custard with whipped cream ( I added a few diced strawberries) or let it cool completely and frost with low carb icing of your choice.

Hope I am not repeating something already posted, but I can't recall ever seeing it here. Hope you enjoy it.