1/2cup(227 grams ounces) unsalted butter, at room temperature
1and 1/2 cups granulated sugar
2large eggs, at room temperature
3teaspoonspure vanilla extract
1cupfull-fat sour cream, at room temperature
Position a rack in the middle of your oven. Preheat oven to 400 degrees (F). Line a 12-cup muffin tin with paper liners and set aside.
In a large bowl, sift together the flour, baking powder, salt, and nutmeg. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment, or in a large bowl using a handheld electric mixer, beat together the butter and sugar on medium speed until light fluffy, about 3 minutes, scraping the bowl as needed.
Add eggs, one at a time, beating well after each addition, and scraping the bottom and sides of the bowl as needed. Add in the vanilla. Turn mixer off.
In a spouted measuring cup, combine sour cream and milk.
With the mixer speed on low, alternate adding flour mixture and sour cream mixture, beginning and ending with the flour, and mixing just until combined. The batter will be very thick, so don't over mix. Turn mixer off.
Using a rubber spatula, gently fold the blueberries into the batter.
Divide batter evenly among prepared muffin tins. Then place muffin tin on a large baking sheet (this extra layer helps ensure your muffin bottoms won't burn).
Bake on the middle rack of your oven for 25 to 27 minutes, or until the tops are golden brown and a toothpick inserted in the middle of a muffin comes out clean.
Cool in the pan, placed on a wire cooling rack, for 10 minutes. Remove muffins from the pan and serve warm.