OK I initially made this recipe and I thought it was good but very dry and dense. and dense So here are some tips. I did substitute the butter for avocado oil, and then I also added an additional tablespoon of avocado oil.
The sour cream I added, was heaping tablespoons, and then I use large, frozen organic, blueberries, that I folded at the end. The result was an outside crispy, crunchy inside, super moist muffin. That was a crowd-pleaser! I also sub bananas for the sugar, this also has really helped in thinning out the badder some. I have also in the past thinned out with a little water.