Strikes me as too much butter & carb. I suggest leaving out the flour completely, & replacing with a mix of ground almonds, soya flour , oat bran, not forgetting baking powder.
I use the 'minute muffin' recipe (search 'muffins'), which allows experiment without wasting ingredients. I find its always edible, & am improving all the time.
I've just made a choc sponge for a little diabetic girl coming to our church club.
ground almond - 50 ml
soya flour 30 ml
cocoa 30 ml
Splenda 30 ml
baking powder 1 tsp
mix dry ingredients thoroughly in a small bowl
1 egg
oil 30 ml
mix thoughly
1 dsp water - for soft 'dropping' consistency
MW on full for 1 1/2 mins
loosen edges & tip out on a rack to cool
About 100 g - 4 g carb, 1 g per portion.
All sorts of variation possible - I leave out the choc & sweetener - add bran, & spices, milled nuts & it makes a useful v low carb 'bread.' (Its bread, Jim, but not as we know it.) Double the quantities & double the cooking time.