Bummer... you need to dirty two bowls for this.

Dump into a microwavable bowl:

1/4 C. Lupin flour
1/2 tsp baking powder
1/4 tsp baking soda (you can omit)
pinch of xanthan gum (optional)
1-3 tsp of cinnamon (or more!)
1-2 Tbl of sweetener (equiv to that amount of sugar)

Mix dry ingredients well.

Using a fork, cut about 1.5 - 2 Tbl of softened butter into the flour mixture until it resembles pills. Like lint that pills up on blankets.

Crack an egg right on top of that mess and stir well until egg is well incorporated. I use jumbo eggs.

Microwave for 1-2 minutes, until dough isn't raw.

Frosting

2+ Tbl of cream cheese
1/4-1/2 tsp vanilla
Sweetener to taste

Mix those together

Pry the muffin out of the bowl (mine release easily) and then frost it!

Absolutely awesome!

Counts using 1 Tbl of cinnamon and no cream cheese:
Calories: 289
Fat: 20g
Protein: 20
Net Carbs: 3.5 (ish)
Fiber: 14.7

Most of the carbs are from the cinnamon (according to My Plan).