I also did the powdered sugar/lemon juice glaze. Added a drop of lemon extract. I like the consistency of the muffin a lot. Very moist. Will make again.
The texture of these muffins wasn't quite what I was expecting, as they turned out to be more like shortbread or a drop biscuit. I agree with one other reviewer in that 20 minutes is just too much time at 400, they just overcook. Most certainly, do not omit the glaze, it's important. These were OK, but I doubt that I'll make again.
Delicious! The batter seemed a bit stiff. I noticed that my carton of yogurt was only 6 ounces, and added 2 ounces of sour cream to make up the difference. I also used a powdered sugar glaze with lemon juice and lemon zest, instead of boiling sugar on the stove.