I doubled the recipe as younger niece was passing through town with 3 friends on their way to Florida for a brief end-of-the-college-semester vacation. The late start brought a few hurry-up steps. Forget bringing the butter to room temperature--I sliced it into thin pieces, threw on the sugar, and started beating in the stand mixer. Once that had something of a start on blending, I stopped the mixer and moved over to measure the rest of my ingredients. First was zesting a large lemon, and tossing the zest into the bowl with the butter and sugar. Dry ingredients: White Lily flour is my bleached AP flour of choice, instead of the Gold Medal or Pillsbury the recipe calls for, and baking powder and salt. (I opted for buttermilk over sour cream, and so used baking powder instead of soda.)
With the dry ingredients blended and the buttermilk ready to go, I went back to the butter-sugar mixture to beat it until fluffy. The egg and vanilla was beaten in, then the mixing moved to a manual process. Half the dry ingredients and half the buttermilk went on top of the butter and were folded in, then the remaining flour and buttermilk, then the "wild" frozen blueberries, straight from the bag as there's no rinsing and drying of frozen berries. As the berries start defrosting on contact with the room-temperature batter I got some streaking in the batter, but I'm not bothered by the cosmetics. (I've used one blueberry muffin recipe that mashes half the berries into the batter for moistness, then folds in the rest.)
I made 6 regular-sized muffins, then managed 23 mini muffins with the remaining batter. I sprinkled on large sugar crystals and grated a bit of fresh nutmeg over each. The sugar crystals seem to have dissolved for the most part, leaving a rather mottled top to the muffins--maybe I was too slow with getting them into the oven and gave the sugar time to melt.
The muffins baked a bit longer than called for due to the frozen berries, but emerged nicely brown and at temperature. The report was that the lemon-blueberry taste was lovely.